diff --git a/src/main/java/cnu/mvc/domain/member/MemberRepository.java b/src/main/java/cnu/mvc/domain/member/MemberRepository.java
index 1b273fc..e2a45c5 100644
--- a/src/main/java/cnu/mvc/domain/member/MemberRepository.java
+++ b/src/main/java/cnu/mvc/domain/member/MemberRepository.java
@@ -22,7 +22,10 @@ public Member findById(Long id) {
 
     // 구현
     public Member findByEmail(String email) {
-        return null;
+        return store.values().stream()
+                .filter(member -> member.getEmail().equals(email))
+                .findFirst()
+                .orElse(null);
     }
 }
 
diff --git a/src/main/java/cnu/mvc/domain/member/MemberService.java b/src/main/java/cnu/mvc/domain/member/MemberService.java
index b8e785e..70b3b9a 100644
--- a/src/main/java/cnu/mvc/domain/member/MemberService.java
+++ b/src/main/java/cnu/mvc/domain/member/MemberService.java
@@ -9,22 +9,30 @@ public class MemberService {
 
     private final MemberRepository memberRepository;
 
-    public Member join(Member member){
+    public Member join(Member member) {
+        if (memberRepository.findByEmail(member.getEmail()) != null) {
+            throw new IllegalArgumentException("이미 존재하는 이메일 계정입니다."); // ✅ 이메일 중복 검증
+        }
         return memberRepository.save(member);
     }
 
     public Member validateMember(String email, String pwd) {
-        Member findMember = findById(1L);
-        return findMember;
+        Member member = memberRepository.findByEmail(email);
+
+        if (member == null || !member.getPwd().equals(pwd)) {
+            throw new IllegalArgumentException("이메일 또는 비밀번호를 확인해주세요."); // ✅ 로그인 검증 실패
+        }
+
+        return member;
     }
 
     public Member findById(Long id) {
         return memberRepository.findById(id);
     }
 
-    // 구현
     public Member findByEmail(String email) {
         return memberRepository.findByEmail(email);
     }
-
 }
+
+