The Pacific sardine, (Sardinops sagax), is a small, coastal pelagic species in the family Clupeidae. Sardine are ecologically important forage for many animals, and have historically supported a large commercial fishery. To expand on previous evolutionary genetic studies of population structure and to test if population structure is present in Pacific sardine was reflective of long-term processes, 434 individuals were examined ranging from Vancouver Island, British Columbia to Bahía Magdalena, Baja California, and from the Gulf of California. A 1062 bp fragment of the cytochrome b gene yielded small but significant fixation estimates of Φ_ST (0.01136, p = 0.032). Concordantly low fixation was observed for two Φ_CT groupings (0.00435, p = 0.128 and 0.00923, p = 0.021). These data support the null hypothesis of an absence of genetic structure in the Pacific sardine.