diff --git a/src/app/api/auth.js b/src/app/api/auth.js
index 3568b69..74f34fd 100644
--- a/src/app/api/auth.js
+++ b/src/app/api/auth.js
@@ -71,4 +71,13 @@ async function userActivation(code) {
   return localClient.post(`/activate?username=${username}&activationkey=0b7b37bb-0f6d-4c65-b1b4-d7cc816f52bd`);
 }
 
-export { login, signup, userPersonalData, userActivation };
+async function existUsername(username) {
+  return authClient.post(`/existsByUsername?username=${username}`);
+}
+
+async function existNickname(nickname) {
+  return authClient.post(`/existsByNickname?nickname=${nickname}`);
+}
+
+
+export { login, signup, userPersonalData, userActivation, existNickname, existUsername };
diff --git a/src/app/screens/RegisterScreen.js b/src/app/screens/RegisterScreen.js
index d1b8414..038d729 100644
--- a/src/app/screens/RegisterScreen.js
+++ b/src/app/screens/RegisterScreen.js
@@ -5,7 +5,13 @@ import {
   ErrorMessage,
 } from "../components/forms";
 import React, { useState, useEffect, useContext } from "react";
-import { StyleSheet, View, Text, TouchableNativeFeedback } from "react-native";
+import {
+  StyleSheet,
+  View,
+  Text,
+  TouchableNativeFeedback,
+  ScrollView,
+} from "react-native";
 import Screen from "../components/Screen";
 import { dimensions } from "../config/dimensions";
 import { MaterialCommunityIcons } from "@expo/vector-icons";
@@ -19,10 +25,16 @@ import SearchablePicker from "../components/SearchablePicker";
 import { states, statesToCities } from "../assets/cities_states";
 import { useFormikContext } from "formik";
 import Checkbox from "../components/forms/CheckBox";
-import {signup, login, userPersonalData} from "../api/auth";
+import {
+  signup,
+  login,
+  userPersonalData,
+  existUsername,
+  existNickname,
+} from "../api/auth";
 import { AuthContext } from "../auth/context";
 import authStorage from "../auth/storage";
-import jwdDecode from "jwt-decode";
+import ConfirmationModal from "../components/ConfirmationModal";
 
 const phoneRegex = RegExp(
   /^\(?[\(]?([0-9]{2})?\)?[)\b]?([0-9]{4,5})[-. ]?([0-9]{4})$/
@@ -236,7 +248,6 @@ function RolePicker({ name }) {
   );
 }
 
-
 function MaterialCommunityIconsCustom({
   name,
   color = colors.primary,
@@ -253,6 +264,8 @@ export default function RegisterScreen(props) {
   const _moment = moment();
   const [date, setDate] = useState(_moment);
   const [singUpFailed, setSingUpFailed] = useState(false);
+  const [scroll, setScroll] = useState();
+  const [showLog, setShowLog] = useState(false);
 
   const comparePassword = (password, confirmPassword) => {
     if (password !== confirmPassword) {
@@ -263,36 +276,57 @@ export default function RegisterScreen(props) {
   };
 
   const automaticLogin = async (form) => {
-    const result = await login(form.number, form.password); 
+    const result = await login(form.number, form.password);
 
     if (!result.ok) return;
-    
+
     authStorage.setToken(result.data);
     const user = await userPersonalData();
     user.ok && authContext.setUser(user.data);
-
-  }
+  };
 
   const handleSubmit = async (form) => {
-    const formDate = date.format("DD/MM/yyyy") === moment().format("DD/MM/yyyy") ? "" : date;
+    console.log("apaaaaaaa");
+    const formDate =
+      date.format("DD/MM/yyyy") === moment().format("DD/MM/yyyy") ? "" : date;
 
-    const result = await signup({...form, dateofborn: formDate})
-    console.log(result)
+    const result = await signup({ ...form, dateofborn: formDate });
+    // console.log(result)
 
     switch (result.status) {
       case 200:
-        automaticLogin(form)
+        automaticLogin(form);
         break;
       case 422:
-        // setError()
-      
-      default:
-        
+      // setError()
     }
   };
 
+  const fieldsAreNotInUse = async (form, actions) => {
+    var inUse = true;
+    const ru = await existUsername(form.number);
+    if (ru.data) {
+      actions.setFieldError("number", "Este número de telefone já está em uso");
+      inUse = false;
+    }
+
+    const rn = await existNickname(form.name);
+    if (rn.data) {
+      actions.setFieldError("name", "Este apelido de usuário já está em uso");
+      inUse = false;
+    }
+
+    return inUse;
+  };
+
   return (
     <Screen style={styles.containter}>
+      <ConfirmationModal
+        show={showLog}
+        description="Apelido de usuário ou telefone em uso"
+        confirmationLabel="OK"
+        onConfirm={() => setShowLog(false)}
+      />
       <Form
         initialValues={{
           name: "",
@@ -309,16 +343,33 @@ export default function RegisterScreen(props) {
           role: "",
           consent: false,
         }}
-        onSubmit={(form) => {
+        onSubmit={(form, actions) => {
           comparePassword(form.password, form.confirmPassword);
-          handleSubmit(form)
+
+          fieldsAreNotInUse(form, actions).then((isNotUsed) => {
+            isNotUsed
+              ? handleSubmit(form)
+              : setShowLog(true)
+              // NOTE: this woud be nice, but does not work...
+              // : scroll.scrollTo({
+              //     x: 0,
+              //     y: 0,
+              //     animated: true,
+              //   });
+          });
         }}
         validationSchema={validationSchema}
       >
         <View
           style={{ flexDirection: "column", justifyContent: "center", flex: 1 }}
         >
-          <KeyboardAwareScrollView scrollEnabled={true}>
+          <ScrollView
+            scrollToOverflowEnabled={true}
+            ref={(ref) => {
+              setScroll(ref);
+            }}
+            scrollEnabled={true}
+          >
             <Text
               style={{
                 color: colors.primary,
@@ -398,25 +449,21 @@ export default function RegisterScreen(props) {
               <MaterialCommunityIconsCustom name="account" />
               <GenderPicker name="gender" />
             </View>
-
             <Text style={styles.labelStyle}>Estado*:</Text>
             <View style={[styles.iconField]}>
               <MaterialCommunityIconsCustom name="map-marker" />
               <StatePicker name="state" />
             </View>
-
             <Text style={styles.labelStyle}>Cidade*:</Text>
             <View style={[styles.iconField]}>
               <MaterialCommunityIconsCustom name="map-marker" />
               <CityPicker name={"city"} />
             </View>
-
             <Text style={styles.labelStyle}>Tipo de instituição:</Text>
             <View style={[styles.iconField]}>
               <MaterialCommunityIconsCustom name="bank" />
               <InstitutionPicker name="institution" />
             </View>
-
             <Text style={styles.labelStyle}>Nome da instituição</Text>
             <View style={styles.iconField}>
               <MaterialCommunityIconsCustom name="bank" />
@@ -429,16 +476,11 @@ export default function RegisterScreen(props) {
                 paddingRight={2}
               />
             </View>
-
-
             <Text style={styles.labelStyle}>Vínculo institucional:</Text>
             <View style={[styles.iconField]}>
               <MaterialCommunityIconsCustom name="bank" />
-              <RolePicker name="role"/>
+              <RolePicker name="role" />
             </View>
-
-
-
             <Text style={styles.labelStyle}>Pergunta de segurança*:</Text>
             <View
               style={{
@@ -461,7 +503,6 @@ export default function RegisterScreen(props) {
                 paddingLeft={2}
               />
             </View>
-
             <Text style={styles.labelStyle}>Termos de uso*</Text>
             <View
               flexDirection="column"
@@ -474,7 +515,6 @@ export default function RegisterScreen(props) {
                 navigate={() => props.navigation.navigate("UserAgreement")}
               />
             </View>
-
             <SubmitButton
               flex={1}
               title="cadastrar"
@@ -497,7 +537,7 @@ export default function RegisterScreen(props) {
                 <Text style={{ color: colors.lightBlue }}>Faça Login</Text>
               </View>
             </TouchableNativeFeedback>
-          </KeyboardAwareScrollView>
+          </ScrollView>
         </View>
       </Form>
     </Screen>