We studied variation in colour pattern and morphology in ten populations of Oophaga pumilio from the Province of Bocas del Toro, western Panama. Our field work documented several distinct phenotypes of colouration and pattern that are highly correlated geographically. On the contrary, variation in the morphometric characters studied is small among these populations. There are examples of distinct populations in close proximity without any obvious physiographic barriers that show no evidence of hybridization. We interpret these abrupt transitions as evidence of lack of or minimal gene flow.