diff --git a/src/main/java/de/hmmh/pmt/ApiController.java b/src/main/java/de/hmmh/pmt/ApiController.java
index 3843178..c14b739 100644
--- a/src/main/java/de/hmmh/pmt/ApiController.java
+++ b/src/main/java/de/hmmh/pmt/ApiController.java
@@ -74,6 +74,48 @@ public class ApiController implements DefaultApi {
         return ResponseEntity.ok(response);
     }
 
+    @Override
+    public ResponseEntity<Void> updateProject(Long id, UpdateProjectDTO body) {
+        Optional<Project> optionalProject = projectRepository.findById(id);
+        if (optionalProject.isEmpty()) {
+            return new ResponseEntity<>(HttpStatus.NOT_FOUND);
+        }
+        Project project = optionalProject.get();
+
+        if (project.getName().equals(body.getName()) && projectRepository.existsByName(body.getName())) {
+            return new ResponseEntity<>(HttpStatus.CONFLICT);
+        }
+
+        if (project.getAdministratorId().equals(body.getAdministratorId())) {
+            HttpStatus status = apiTools.checkEmployeeExists(body.getAdministratorId()).status();
+            if (status != HttpStatus.OK) {
+                return new ResponseEntity<>(status);
+            }
+        }
+
+        Project finalProject = mapper.map(project, body);
+        if (!validator.isValidProject(project)) {
+            return new ResponseEntity<>(HttpStatus.UNPROCESSABLE_ENTITY);
+        }
+
+        if (validator.areAllocationTimeRangesOverlapping(
+                project.getStart(),
+                project.getPlannedEnd(),
+                allocationRepository
+                        .findAllByProjectId(finalProject.getId())
+                        .stream()
+                        .map(Allocation::getEmployeeId)
+                        .flatMap(employeeId -> allocationRepository.findAllByEmployeeId(employeeId).stream())
+                        .filter(employeeAllocation -> employeeAllocation.getProjectId().equals(finalProject.getId()))
+                        .toList()
+        )){
+            return new ResponseEntity<>(HttpStatus.UNPROCESSABLE_ENTITY);
+        }
+
+        projectRepository.save(project);
+        return new ResponseEntity<>(HttpStatus.NO_CONTENT);
+    }
+
     @Override
     public ResponseEntity<CreatedProjectDTO> createProject(CreateProjectDTO body) {
         if (projectRepository.existsByName(body.getName())) {
diff --git a/src/main/java/de/hmmh/pmt/util/Mapper.java b/src/main/java/de/hmmh/pmt/util/Mapper.java
index 09ba201..dd0b7f7 100644
--- a/src/main/java/de/hmmh/pmt/util/Mapper.java
+++ b/src/main/java/de/hmmh/pmt/util/Mapper.java
@@ -7,6 +7,7 @@ import de.hmmh.pmt.dtos.Employee;
 import de.hmmh.pmt.dtos.Qualification ;
 import de.hmmh.pmt.employee.dtos.EmployeeResponseDTO;
 import de.hmmh.pmt.employee.dtos.QualificationGetDTO;
+import de.hmmh.pmt.dtos.UpdateProjectDTO;
 import org.springframework.stereotype.Component;
 
 import java.util.List;
@@ -61,4 +62,15 @@ public class Mapper {
         return dto;
     }
 
+
+    public Project map(Project project, UpdateProjectDTO dto) {
+        project.setName(dto.getName());
+        project.setGoal(dto.getGoal());
+        project.setCustomerId(dto.getCustomerId());
+        project.setAdministratorId(dto.getAdministratorId());
+        project.setStart(dto.getStart());
+        project.setPlannedEnd(dto.getPlannedEnd());
+        project.setRealEnd(dto.getEnd());
+        return project;
+    }
 }