Fertilization triggers Ca2+ increase and alkalization in the eggs of some species such as the frog. Oopiasmic Ca2+ increase triggers fertilization potential (FP), and alkalization can have a permissive effect in Ca2+ increase. It can be expected that pH regulation in the egg can affect both ooplasmic Ca2+ levels and the events triggered by increasing Ca2+. The evidence of the possibility of H+-K+ ATPase in different tissues in recent studies prompted us to wonder about the probability of the existence of this pump in the egg. Therefore, we decided to investigate the presence of H+-K+ ATPase by bioelectrical potential recordings in frog eggs. Thus, frog eggs were inseminated while the resting membrane potential (RMP) in the solution containing different concentrations (0.3, 0.6, 0.9 and 1.2 mM) of pump inhibitors (omeprazole and lansoprazole) was recorded. Evidence of H+-K+ ATPase was sought from the effects of these pump inhibitors on FP variables.