diff --git a/internal/rdb/rdb.go b/internal/rdb/rdb.go
index f3875d5..e31c1d6 100644
--- a/internal/rdb/rdb.go
+++ b/internal/rdb/rdb.go
@@ -1155,15 +1155,30 @@ func (r *RDB) DeleteAggregationSet(ctx context.Context, qname, gname, setID stri
 	return r.runScript(ctx, op, deleteAggregationSetCmd, []string{base.AggregationSetKey(qname, gname, setID)}, base.TaskKeyPrefix(qname))
 }
 
+// KEYS[1] -> asynq:{<qname>}:aggregation_sets
+// -------
+// ARGV[1] -> current time in unix time
 var reclaimStateAggregationSetsCmd = redis.NewScript(`
-
+local staleSetKeys = redis.call("ZRANGEBYSCORE", KEYS[1], "-inf", ARGV[1])
+for _, key in ipairs(staleSetKeys) do
+	local idx = string.find(key, ":[^:]*$")
+	local groupKey = string.sub(key, 1, idx-1)
+	local res = redis.call("ZRANGE", key, 0, -1, "WITHSCORES")
+	for i=1, table.getn(res)-1, 2 do
+		redis.call("ZADD", groupKey, tonumber(res[i+1]), res[i])
+	end
+	redis.call("DEL", key)
+end
+redis.call("ZREMRANGEBYSCORE", KEYS[1], "-inf", ARGV[1])
+return redis.status_reply("OK")
 `)
 
 // ReclaimStateAggregationSets checks for any stale aggregation sets in the given queue, and
 // reclaim tasks in the stale aggregation set by putting them back in the group.
 func (r *RDB) ReclaimStaleAggregationSets(qname string) error {
-	//now := r.clock.Now()
-	return nil
+	var op errors.Op = "RDB.ReclaimStaleAggregationSets"
+	return r.runScript(context.Background(), op, reclaimStateAggregationSetsCmd,
+		[]string{base.AllAggregationSets(qname)}, r.clock.Now().Unix())
 }
 
 // KEYS[1] -> asynq:{<qname>}:completed
diff --git a/internal/rdb/rdb_test.go b/internal/rdb/rdb_test.go
index d5ceaed..f9c72d3 100644
--- a/internal/rdb/rdb_test.go
+++ b/internal/rdb/rdb_test.go
@@ -9,6 +9,7 @@ import (
 	"encoding/json"
 	"flag"
 	"math"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -3513,12 +3514,26 @@ func AssertZSets(t *testing.T, r redis.UniversalClient, wantZSets map[string][]r
 		if err != nil {
 			t.Fatalf("Failed to read zset (key=%q): %v", key, err)
 		}
-		if diff := cmp.Diff(want, got); diff != "" {
+		if diff := cmp.Diff(want, got, SortZSetEntryOpt); diff != "" {
 			t.Errorf("mismatch found in zset (key=%q): (-want,+got)\n%s", key, diff)
 		}
 	}
 }
 
+var SortZSetEntryOpt = cmp.Transformer("SortZSetEntries", func(in []redis.Z) []redis.Z {
+	out := append([]redis.Z(nil), in...) // Copy input to avoid mutating it
+	sort.Slice(out, func(i, j int) bool {
+		// TODO: If member is a comparable type (int, string, etc) compare by the member
+		// Use generic comparable type here once update to go1.18
+		if _, ok := out[i].Member.(string); ok {
+			// If member is a string, compare the member
+			return out[i].Member.(string) < out[j].Member.(string)
+		}
+		return out[i].Score < out[j].Score
+	})
+	return out
+})
+
 func TestListGroups(t *testing.T) {
 	r := setup(t)
 	defer r.Close()