diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0097fb829b..a5388cc089 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changes
 
 - Optimization of mutex usage in cache for reaper [#3286](https://github.com/evstack/ev-node/pull/3286)
+- Reduce tx cache retention to avoid OOM under (really) heavy tx load [#3299](https://github.com/evstack/ev-node/pull/3299)
 
 ## v1.1.1
 
diff --git a/block/internal/cache/manager.go b/block/internal/cache/manager.go
index e907002600..4d95a7d7e5 100644
--- a/block/internal/cache/manager.go
+++ b/block/internal/cache/manager.go
@@ -26,7 +26,8 @@ const (
 	DataDAIncludedPrefix = "cache/data-da-included/"
 
 	// DefaultTxCacheRetention is the default time to keep transaction hashes in cache.
-	DefaultTxCacheRetention = 24 * time.Hour
+	// Keeping a too high value can lead to OOM during heavy transaction load.
+	DefaultTxCacheRetention = 30 * time.Minute
 )
 
 // CacheManager provides thread-safe cache operations for tracking seen blocks
diff --git a/block/internal/reaping/reaper.go b/block/internal/reaping/reaper.go
index d35dbfff3e..1f51c08f10 100644
--- a/block/internal/reaping/reaper.go
+++ b/block/internal/reaping/reaper.go
@@ -21,7 +21,10 @@ import (
 const (
 	// MaxBackoffInterval is the maximum backoff interval for retries
 	MaxBackoffInterval = 30 * time.Second
-	CleanupInterval    = 1 * time.Hour
+
+	// CleanupInterval is how often the reaper sweeps expired hashes
+	// out of the seen-tx cache.
+	CleanupInterval = max(cache.DefaultTxCacheRetention/10, 15*time.Second)
 )
 
 // Reaper is responsible for periodically retrieving transactions from the executor,