diff --git a/.changelog/5466.cfg.md b/.changelog/5466.cfg.md
new file mode 100644
index 00000000000..0d15c870df8
--- /dev/null
+++ b/.changelog/5466.cfg.md
@@ -0,0 +1,4 @@
+Add `num_light_blocks_kept` configuration option
+
+Located under `consensus.prune`, it allows configuring the number of light
+blocks that are kept in the local trusted store (defaulting to 10000).
diff --git a/go/consensus/cometbft/abci/prune.go b/go/consensus/cometbft/abci/prune.go
index 307b9a4146b..16351a50829 100644
--- a/go/consensus/cometbft/abci/prune.go
+++ b/go/consensus/cometbft/abci/prune.go
@@ -9,16 +9,11 @@ import (
 
 	"github.com/oasisprotocol/oasis-core/go/common/logging"
 	"github.com/oasisprotocol/oasis-core/go/consensus/cometbft/api"
+	"github.com/oasisprotocol/oasis-core/go/consensus/cometbft/config"
 	nodedb "github.com/oasisprotocol/oasis-core/go/storage/mkvs/db/api"
 )
 
 const (
-	// PruneDefault is the default PruneStrategy.
-	PruneDefault = pruneNone
-
-	pruneNone  = "none"
-	pruneKeepN = "keep_n"
-
 	// LogEventABCIPruneDelete is a log event value that signals an ABCI pruning
 	// delete event.
 	LogEventABCIPruneDelete = "cometbft/abci/prune"
@@ -38,9 +33,9 @@ const (
 func (s PruneStrategy) String() string {
 	switch s {
 	case PruneNone:
-		return pruneNone
+		return config.PruneStrategyNone
 	case PruneKeepN:
-		return pruneKeepN
+		return config.PruneStrategyKeepN
 	default:
 		return "[unknown]"
 	}
@@ -48,9 +43,9 @@ func (s PruneStrategy) String() string {
 
 func (s *PruneStrategy) FromString(str string) error {
 	switch strings.ToLower(str) {
-	case pruneNone:
+	case config.PruneStrategyNone:
 		*s = PruneNone
-	case pruneKeepN:
+	case config.PruneStrategyKeepN:
 		*s = PruneKeepN
 	default:
 		return fmt.Errorf("abci/pruner: unknown pruning strategy: '%v'", str)
diff --git a/go/consensus/cometbft/config/config.go b/go/consensus/cometbft/config/config.go
index 6f5251cd10f..bffbf2356ce 100644
--- a/go/consensus/cometbft/config/config.go
+++ b/go/consensus/cometbft/config/config.go
@@ -87,6 +87,13 @@ type SubmissionConfig struct {
 	MaxFee uint64 `yaml:"max_fee"`
 }
 
+const (
+	// PruneStrategyNone is the identifier of the strategy that disables pruning.
+	PruneStrategyNone = "none"
+	// PruneStrategyKeepN is the identifier of the strategy that keeps the last N versions.
+	PruneStrategyKeepN = "keep_n"
+)
+
 // PruneConfig is the CometBFT ABCI state pruning configuration structure.
 type PruneConfig struct {
 	// ABCI state pruning strategy.
@@ -95,6 +102,8 @@ type PruneConfig struct {
 	NumKept uint64 `yaml:"num_kept"`
 	// ABCI state pruning interval.
 	Interval time.Duration `yaml:"interval"`
+	// Light blocks kept in trusted store.
+	NumLightBlocksKept uint16 `yaml:"num_light_blocks_kept"`
 }
 
 // CheckpointerConfig is the CometBFT ABCI state pruning configuration structure.
@@ -200,9 +209,10 @@ func DefaultConfig() Config {
 		HaltHeight:       0,
 		UpgradeStopDelay: 60 * time.Second,
 		Prune: PruneConfig{
-			Strategy: "none",
-			NumKept:  3600,
-			Interval: 2 * time.Minute,
+			Strategy:           PruneStrategyNone,
+			NumKept:            3600,
+			Interval:           2 * time.Minute,
+			NumLightBlocksKept: 10000,
 		},
 		Checkpointer: CheckpointerConfig{
 			Disabled:      false,
diff --git a/go/consensus/cometbft/light/service.go b/go/consensus/cometbft/light/service.go
index 4c12ab13073..b3578b803f3 100644
--- a/go/consensus/cometbft/light/service.go
+++ b/go/consensus/cometbft/light/service.go
@@ -21,8 +21,8 @@ import (
 	"github.com/oasisprotocol/oasis-core/go/config"
 	consensus "github.com/oasisprotocol/oasis-core/go/consensus/api"
 	cmtAPI "github.com/oasisprotocol/oasis-core/go/consensus/cometbft/api"
-	tmapi "github.com/oasisprotocol/oasis-core/go/consensus/cometbft/api"
 	"github.com/oasisprotocol/oasis-core/go/consensus/cometbft/common"
+	cmtConfig "github.com/oasisprotocol/oasis-core/go/consensus/cometbft/config"
 	"github.com/oasisprotocol/oasis-core/go/consensus/cometbft/db"
 	"github.com/oasisprotocol/oasis-core/go/consensus/cometbft/light/api"
 	p2pLight "github.com/oasisprotocol/oasis-core/go/consensus/cometbft/light/p2p"
@@ -151,7 +151,7 @@ func (c *client) worker() {
 		c.logger.Error("failed to obtain chain context", "err", err)
 		return
 	}
-	tmChainID := tmapi.CometBFTChainID(chainCtx)
+	tmChainID := cmtAPI.CometBFTChainID(chainCtx)
 
 	// Loads the local block at the provided height and adds it to the trust store.
 	trustLocalBlock := func(ctx context.Context, height int64) error {
@@ -208,15 +208,26 @@ func (c *client) worker() {
 		providers = append(providers, p)
 		c.providers = append(c.providers, p)
 	}
+
+	opts := []cmtlight.Option{
+		cmtlight.MaxRetryAttempts(lcMaxRetryAttempts),
+		cmtlight.Logger(common.NewLogAdapter(!config.GlobalConfig.Consensus.LogDebug)),
+		cmtlight.DisableProviderRemoval(),
+	}
+	switch config.GlobalConfig.Consensus.Prune.Strategy {
+	case cmtConfig.PruneStrategyNone:
+		opts = append(opts, cmtlight.PruningSize(0)) // Disable pruning the light store.
+	default:
+		opts = append(opts, cmtlight.PruningSize(config.GlobalConfig.Consensus.Prune.NumLightBlocksKept))
+	}
+
 	tmc, err := cmtlight.NewClientFromTrustedStore(
 		tmChainID,
 		config.GlobalConfig.Consensus.StateSync.TrustPeriod,
 		providers[0],  // Primary provider.
 		providers[1:], // Witnesses.
 		c.store,
-		cmtlight.MaxRetryAttempts(lcMaxRetryAttempts),
-		cmtlight.Logger(common.NewLogAdapter(!config.GlobalConfig.Consensus.LogDebug)),
-		cmtlight.DisableProviderRemoval(),
+		opts...,
 	)
 	if err != nil {
 		c.logger.Error("failed to initialize cometbft light client", "err", err)