diff --git a/CHANGELOG.md b/CHANGELOG.md
index e23cace553b..1d1851e713a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,7 +22,7 @@
 * [CHANGE] Ingester client: experimental support for client-side circuit breakers, their configuration options (`-ingester.client.circuit-breaker.*`) and metrics (`cortex_ingester_client_circuit_breaker_results_total`, `cortex_ingester_client_circuit_breaker_transitions_total`) were removed. #8802
 * [CHANGE] Ingester: circuit breakers do not open in case of per-instance limit errors anymore. Opening can be triggered only in case of push and pull requests exceeding the configured duration. #8854
 * [CHANGE] Query-frontend: Return `413 Request Entity Too Large` if a response shard for an `/active_series` request is too large. #8861
-* [FEATURE] Querier: add experimental streaming PromQL engine, enabled with `-querier.query-engine=mimir`. #8422 #8430 #8454 #8455 #8360 #8490 #8508 #8577 #8660 #8671 #8677 #8747 #8850 #8872 #8838 #8911 #8909 #8923 #8924 #8925 #8932 #8933 #8934 #8962 #8986 #8993
+* [CHANGE] Ingester: increase the default inactivity timeout of active series (`-ingester.active-series-metrics-idle-timeout`) from `10m` to `20m`. #8975* [FEATURE] Querier: add experimental streaming PromQL engine, enabled with `-querier.query-engine=mimir`. #8422 #8430 #8454 #8455 #8360 #8490 #8508 #8577 #8660 #8671 #8677 #8747 #8850 #8872 #8838 #8911 #8909 #8923 #8924 #8925 #8932 #8933 #8934 #8962 #8986 #8993
 * [FEATURE] Experimental Kafka-based ingest storage. #6888 #6894 #6929 #6940 #6951 #6974 #6982 #7029 #7030 #7091 #7142 #7147 #7148 #7153 #7160 #7193 #7349 #7376 #7388 #7391 #7393 #7394 #7402 #7404 #7423 #7424 #7437 #7486 #7503 #7508 #7540 #7621 #7682 #7685 #7694 #7695 #7696 #7697 #7701 #7733 #7734 #7741 #7752 #7838 #7851 #7871 #7877 #7880 #7882 #7887 #7891 #7925 #7955 #7967 #8031 #8063 #8077 #8088 #8135 #8176 #8184 #8194 #8216 #8217 #8222 #8233 #8503 #8542 #8579 #8657 #8686 #8688 #8703 #8706 #8708 #8738 #8750 #8778 #8808 #8809 #8841 #8842 #8845 #8853 #8886
   * What it is:
     * When the new ingest storage architecture is enabled, distributors write incoming write requests to a Kafka-compatible backend, and the ingesters asynchronously replay ingested data from Kafka. In this architecture, the write and read path are de-coupled through a Kafka-compatible backend. The write path and Kafka load is a function of the incoming write traffic, the read path load is a function of received queries. Whatever the load on the read path, it doesn't affect the write path.
diff --git a/cmd/mimir/config-descriptor.json b/cmd/mimir/config-descriptor.json
index c5c00780836..b6003d8ec54 100644
--- a/cmd/mimir/config-descriptor.json
+++ b/cmd/mimir/config-descriptor.json
@@ -3278,7 +3278,7 @@
           "required": false,
           "desc": "After what time a series is considered to be inactive.",
           "fieldValue": null,
-          "fieldDefaultValue": 600000000000,
+          "fieldDefaultValue": 1200000000000,
           "fieldFlag": "ingester.active-series-metrics-idle-timeout",
           "fieldType": "duration",
           "fieldCategory": "advanced"
diff --git a/cmd/mimir/help-all.txt.tmpl b/cmd/mimir/help-all.txt.tmpl
index f3209849174..8633cfbca29 100644
--- a/cmd/mimir/help-all.txt.tmpl
+++ b/cmd/mimir/help-all.txt.tmpl
@@ -1368,7 +1368,7 @@ Usage of ./cmd/mimir/mimir:
   -ingester.active-series-metrics-enabled
     	Enable tracking of active series and export them as metrics. (default true)
   -ingester.active-series-metrics-idle-timeout duration
-    	After what time a series is considered to be inactive. (default 10m0s)
+    	After what time a series is considered to be inactive. (default 20m0s)
   -ingester.active-series-metrics-update-period duration
     	How often to update active series metrics. (default 1m0s)
   -ingester.client.backoff-max-period duration
diff --git a/docs/sources/mimir/configure/configuration-parameters/index.md b/docs/sources/mimir/configure/configuration-parameters/index.md
index 0d64394f60d..4cc8b6b76cf 100644
--- a/docs/sources/mimir/configure/configuration-parameters/index.md
+++ b/docs/sources/mimir/configure/configuration-parameters/index.md
@@ -1200,7 +1200,7 @@ partition_ring:
 
 # (advanced) After what time a series is considered to be inactive.
 # CLI flag: -ingester.active-series-metrics-idle-timeout
-[active_series_metrics_idle_timeout: <duration> | default = 10m]
+[active_series_metrics_idle_timeout: <duration> | default = 20m]
 
 # (experimental) Period with which to update the per-tenant TSDB configuration.
 # CLI flag: -ingester.tsdb-config-update-period
diff --git a/pkg/ingester/activeseries/active_series.go b/pkg/ingester/activeseries/active_series.go
index 7df6d102259..1f957784f49 100644
--- a/pkg/ingester/activeseries/active_series.go
+++ b/pkg/ingester/activeseries/active_series.go
@@ -34,7 +34,7 @@ type Config struct {
 func (cfg *Config) RegisterFlags(f *flag.FlagSet) {
 	f.BoolVar(&cfg.Enabled, EnabledFlag, true, "Enable tracking of active series and export them as metrics.")
 	f.DurationVar(&cfg.UpdatePeriod, "ingester.active-series-metrics-update-period", 1*time.Minute, "How often to update active series metrics.")
-	f.DurationVar(&cfg.IdleTimeout, IdleTimeoutFlag, 10*time.Minute, "After what time a series is considered to be inactive.")
+	f.DurationVar(&cfg.IdleTimeout, IdleTimeoutFlag, 20*time.Minute, "After what time a series is considered to be inactive.")
 }
 
 // ActiveSeries is keeping track of recently active series for a single tenant.