diff --git a/apps/server/db/query/problem.sql b/apps/server/db/query/problem.sql
index 3c989ee..3fae95a 100644
--- a/apps/server/db/query/problem.sql
+++ b/apps/server/db/query/problem.sql
@@ -135,3 +135,15 @@ LIMIT $1 OFFSET $2;
 -- name: CountAllProblems :one
 SELECT COUNT(*) FROM problems
 WHERE archived_at IS NULL;
+-- name: CheckProblemInActiveAssignments :one
+SELECT COUNT(*)
+FROM assignment_problems ap
+JOIN assignments a ON ap.assignment_id = a.id
+WHERE ap.problem_id = $1
+  AND a.status = 'active'
+  AND a.archived_at IS NULL;
+
+-- name: CheckProblemInAssignmentGroups :one
+SELECT COUNT(*)
+FROM assignment_group_problems
+WHERE problem_id = $1;
diff --git a/apps/server/go.mod b/apps/server/go.mod
index f8d76d9..0c09ae6 100644
--- a/apps/server/go.mod
+++ b/apps/server/go.mod
@@ -1,6 +1,6 @@
 module github.com/coderz-space/coderz.space
 
-go 1.24.3
+go 1.25.0
 
 require (
 	github.com/go-playground/validator/v10 v10.30.1
diff --git a/apps/server/internal/db/sqlc/assignment.sql.go b/apps/server/internal/db/sqlc/assignment.sql.go
index d9a5667..805558b 100644
--- a/apps/server/internal/db/sqlc/assignment.sql.go
+++ b/apps/server/internal/db/sqlc/assignment.sql.go
@@ -279,7 +279,7 @@ func (q *Queries) GetAssignmentGroup(ctx context.Context, id pgtype.UUID) (Assig
 }
 
 const getAssignmentProblem = `-- name: GetAssignmentProblem :one
-SELECT ap.id, ap.assignment_id, ap.problem_id, ap.status, ap.solution_link, ap.notes, ap.completed_at, ap.created_at, ap.updated_at, p.title, p.difficulty 
+SELECT ap.id, ap.assignment_id, ap.problem_id, ap.status, ap.solution_link, ap.notes, ap.completed_at, ap.created_at, ap.updated_at, p.title, p.difficulty
 FROM assignment_problems ap
 JOIN problems p ON ap.problem_id = p.id
 WHERE ap.assignment_id = $1 AND ap.problem_id = $2
@@ -564,7 +564,7 @@ func (q *Queries) ListAssignmentGroupsByBootcamp(ctx context.Context, arg ListAs
 }
 
 const listAssignmentProblemsStatus = `-- name: ListAssignmentProblemsStatus :many
-SELECT ap.id, ap.assignment_id, ap.problem_id, ap.status, ap.solution_link, ap.notes, ap.completed_at, ap.created_at, ap.updated_at, p.title, p.difficulty 
+SELECT ap.id, ap.assignment_id, ap.problem_id, ap.status, ap.solution_link, ap.notes, ap.completed_at, ap.created_at, ap.updated_at, p.title, p.difficulty
 FROM assignment_problems ap
 JOIN problems p ON ap.problem_id = p.id
 WHERE ap.assignment_id = $1
diff --git a/apps/server/internal/db/sqlc/problem.sql.go b/apps/server/internal/db/sqlc/problem.sql.go
index ab85fa8..c926bac 100644
--- a/apps/server/internal/db/sqlc/problem.sql.go
+++ b/apps/server/internal/db/sqlc/problem.sql.go
@@ -643,3 +643,32 @@ func (q *Queries) UpdateTag(ctx context.Context, arg UpdateTagParams) (Tag, erro
 	)
 	return i, err
 }
+
+const checkProblemInActiveAssignments = `-- name: CheckProblemInActiveAssignments :one
+SELECT COUNT(*)
+FROM assignment_problems ap
+JOIN assignments a ON ap.assignment_id = a.id
+WHERE ap.problem_id = $1
+  AND a.status = 'active'
+  AND a.archived_at IS NULL
+`
+
+func (q *Queries) CheckProblemInActiveAssignments(ctx context.Context, problemID pgtype.UUID) (int64, error) {
+	row := q.db.QueryRow(ctx, checkProblemInActiveAssignments, problemID)
+	var count int64
+	err := row.Scan(&count)
+	return count, err
+}
+
+const checkProblemInAssignmentGroups = `-- name: CheckProblemInAssignmentGroups :one
+SELECT COUNT(*)
+FROM assignment_group_problems
+WHERE problem_id = $1
+`
+
+func (q *Queries) CheckProblemInAssignmentGroups(ctx context.Context, problemID pgtype.UUID) (int64, error) {
+	row := q.db.QueryRow(ctx, checkProblemInAssignmentGroups, problemID)
+	var count int64
+	err := row.Scan(&count)
+	return count, err
+}
diff --git a/apps/server/internal/modules/problem/service.go b/apps/server/internal/modules/problem/service.go
index f45f1f3..7cf0c9d 100644
--- a/apps/server/internal/modules/problem/service.go
+++ b/apps/server/internal/modules/problem/service.go
@@ -128,8 +128,24 @@ func (s *Service) UpdateProblem(ctx context.Context, req UpdateProblemRequest, p
 }
 
 func (s *Service) DeleteProblem(ctx context.Context, problemID pgtype.UUID) error {
-	// TODO: Check if problem is referenced by assignments (requires assignment queries)
-	// For now, just archive the problem
+	// Check if problem is referenced by active assignments
+	activeCount, err := s.queries.CheckProblemInActiveAssignments(ctx, problemID)
+	if err != nil {
+		return err
+	}
+	if activeCount > 0 {
+		return errors.New("cannot delete problem: referenced by active assignments")
+	}
+
+	// Check if problem is referenced by assignment groups
+	groupCount, err := s.queries.CheckProblemInAssignmentGroups(ctx, problemID)
+	if err != nil {
+		return err
+	}
+	if groupCount > 0 {
+		return errors.New("cannot delete problem: referenced by assignment groups")
+	}
+
 	return s.queries.ArchiveProblem(ctx, problemID)
 }