Several studies have demonstrated that polyploid species can form recurrently from their progenitors, but few studies have evaluated gene flow between the resultant polyploid lineages. Here we examine the possibility of hybridization between lineages of the tetraploid common gray treefrog (Hyla versicolor). We utilize a polymerase chain reaction (PCR) cloning approach to estimate the genotypes of tetraploid individuals and measure genetic differentiation between (1) sympatric populations of two lineages and (2) allopatric populations of a single lineage. We find that allele frequencies in sympatric populations of two lineages do not differ, suggesting that frogs of these two lineages hybridize in areas where they co-occur.