Base lesions in DNA can stall the replication machinery or induce mutations if bypassed. Consequently, lesions must be repaired before replication or in a post-replicative process to maintain genomic stability. Base excision repair (BER) is the main pathway for repair of base lesions, but how BER is organized during DNA replication is unclear. Here we refined the iPOND (isolation of proteins on nascent DNA) technique with targeted mass-spectrometry analysis, which enabled us to detect all proteins required for BER on nascent DNA and to monitor their spatiotemporal orchestration at replication forks. We demonstrate that XRCC1 and other BER/single-strand break repair (SSBR) proteins are enriched in replisomes in unstressed cells, supporting a cellular capacity of post-replicative BER/SSBR. Importantly, the DNA glycosylases MYH, UNG2, MPG, NTH1, NEIL1 and NEIL3 were also detected on nascent DNA. Thus our findings reveal that a broad spectrum of DNA base lesions are recognized and repaired by BER in a post-replicative process.