diff --git a/repository/job.go b/repository/job.go
index d6866ca..8c2d339 100644
--- a/repository/job.go
+++ b/repository/job.go
@@ -11,6 +11,7 @@ import (
 
 	"github.com/ClusterCockpit/cc-backend/auth"
 	"github.com/ClusterCockpit/cc-backend/graph/model"
+	"github.com/ClusterCockpit/cc-backend/log"
 	"github.com/ClusterCockpit/cc-backend/schema"
 	sq "github.com/Masterminds/squirrel"
 	"github.com/iamlouk/lrucache"
@@ -370,3 +371,26 @@ func (r *JobRepository) AllocatedNodes(cluster string) (map[string]map[string]in
 
 	return subclusters, nil
 }
+
+func (r *JobRepository) StopJobsExceedingWalltimeBy(seconds int) error {
+	res, err := sq.Update("job").
+		Set("monitoring_status", schema.MonitoringStatusArchivingFailed).
+		Set("duration", 0).
+		Set("job_state", schema.JobStateFailed).
+		Where("job.job_state = 'running'").
+		Where(fmt.Sprintf("(%d - job.start_time) > (job.walltime + %d)", time.Now().Unix(), seconds)).
+		RunWith(r.DB).Exec()
+	if err != nil {
+		return err
+	}
+
+	rowsAffected, err := res.RowsAffected()
+	if err != nil {
+		return err
+	}
+
+	if rowsAffected > 0 {
+		log.Warnf("%d jobs have been marked as failed due to running too long", rowsAffected)
+	}
+	return nil
+}
diff --git a/server.go b/server.go
index 28f210a..c9a5ae2 100644
--- a/server.go
+++ b/server.go
@@ -13,6 +13,7 @@ import (
 	"net/url"
 	"os"
 	"os/signal"
+	"runtime"
 	"runtime/debug"
 	"strings"
 	"sync"
@@ -92,6 +93,9 @@ type ProgramConfig struct {
 
 	// Where to store MachineState files
 	MachineStateDir string `json:"machine-state-dir"`
+
+	// If not zero, automatically mark jobs as stopped running X seconds longer than theire walltime.
+	StopJobsExceedingWalltime int `json:"stop-jobs-exceeding-walltime"`
 }
 
 var programConfig ProgramConfig = ProgramConfig{
@@ -123,6 +127,7 @@ var programConfig ProgramConfig = ProgramConfig{
 		"plot_view_showStatTable":            true,
 		"system_view_selectedMetric":         "cpu_load",
 	},
+	StopJobsExceedingWalltime: 3600,
 }
 
 func main() {
@@ -477,6 +482,18 @@ func main() {
 		api.OngoingArchivings.Wait()
 	}()
 
+	if programConfig.StopJobsExceedingWalltime != 0 {
+		go func() {
+			for range time.Tick(1 * time.Hour) {
+				err := jobRepo.StopJobsExceedingWalltimeBy(programConfig.StopJobsExceedingWalltime)
+				if err != nil {
+					log.Errorf("error while looking for jobs exceeding theire walltime: %s", err.Error())
+				}
+				runtime.GC()
+			}
+		}()
+	}
+
 	if os.Getenv("GOGC") == "" {
 		debug.SetGCPercent(25)
 	}