diff --git a/packages/beacon-node/src/chain/chain.ts b/packages/beacon-node/src/chain/chain.ts
index 694cb5495958..7050d7462f4e 100644
--- a/packages/beacon-node/src/chain/chain.ts
+++ b/packages/beacon-node/src/chain/chain.ts
@@ -806,7 +806,7 @@ export class BeaconChain implements IBeaconChain {
       sleep((1000 * this.config.SECONDS_PER_SLOT) / 2)
         .then(() => metrics.onceEveryEndOfEpoch(this.getHeadState()))
         .catch((e) => {
-          if (!isErrorAborted(e)) this.logger.error("error on validator monitor onceEveryEndOfEpoch", {slot}, e);
+          if (!isErrorAborted(e)) this.logger.error("Error on validator monitor onceEveryEndOfEpoch", {slot}, e);
         });
     }
   }
diff --git a/packages/beacon-node/src/metrics/validatorMonitor.ts b/packages/beacon-node/src/metrics/validatorMonitor.ts
index de350c36ccbe..bc2bc268ed23 100644
--- a/packages/beacon-node/src/metrics/validatorMonitor.ts
+++ b/packages/beacon-node/src/metrics/validatorMonitor.ts
@@ -15,6 +15,7 @@ import {ChainConfig, ChainForkConfig} from "@lodestar/config";
 import {ForkSeq, INTERVALS_PER_SLOT, MIN_ATTESTATION_INCLUSION_DELAY, SLOTS_PER_EPOCH} from "@lodestar/params";
 import {Epoch, Slot, ValidatorIndex} from "@lodestar/types";
 import {IndexedAttestation, SignedAggregateAndProof} from "@lodestar/types/phase0";
+import {GENESIS_SLOT} from "../constants/constants.js";
 import {LodestarMetrics} from "./metrics/lodestar.js";
 
 /** The validator monitor collects per-epoch data about each monitored validator.
@@ -607,6 +608,11 @@ export function createValidatorMonitor(
     // To guard against short re-orgs it will track the status of epoch N at the end of epoch N+1.
     // This function **SHOULD** be called at the last slot of an epoch to have max possible information.
     onceEveryEndOfEpoch(headState) {
+      if (headState.slot <= GENESIS_SLOT) {
+        // Before genesis, there won't be any validator activity
+        return;
+      }
+
       // Prune validators not seen in a while
       for (const [index, validator] of validators.entries()) {
         if (Date.now() - validator.lastRegisteredTimeMs > RETAIN_REGISTERED_VALIDATORS_MS) {