Meiosis is essential for generating haploid gametes during sexual reproduction. In the course of meiotic prophase 1, homologous recombination is accompanied by dynamic chromosomal changes. The Ce-rdh-1/rad-51 gene is the only bacterial recA-like gene in the nematode Caenorhabditis elegans genome. Upon depletion of Ce-rdh-1/rad-51 using the RNA interference method, abnormal ”kinked” chromosomes can be observed in mature oocytes at diakinesis, whereas synapsis between homologous chromosomes during the pachytene stage is normal. Following fertilization, Ce-rdh-1/rad-51-depleted embryos die early in embryogenesis. From epistasis analyses with Ce-spo-11 defective mutant and ionizing radiation, it is indicated that Ce-rdh-1/rad-51 functions after double-strand break (DSB) formation of meiotic recombination. Under the Ce-chk-2 defective condition, whose meiotic synapsis and meiotic recombination between homologous chromosomes are completely inhibited, the Ce-rdh-1/rad51 is normally expressed in the gonadal cells. Moreover, it seems that exogenous DSBs in the Ce-chk-2 defective nuclei at pachytene stage can be repaired between sister chromatids by Ce-rdh-1/rad-51 dependent manner. These results indicate that Ce-rdh-1/rad51 functions after both endogenous and exogenous DSBs formation during meiosis, but not as ”pairing centers” for meiotic synapsis. We also found that the syp-1, syp-2 and syp-3 genes are essential for meiotic synapsis at pachytene stage.