Allozyme and C-banding studies on Triturus alpestris cyreni from north and central Spain and of T. a. alpestris from west and central Europe show a distinct differentiation between the taxa. Within the Iberian subspecies a marked genetic differentiation is detected among those populations that are geographically isolated, with the exception of that from central Spain. One of the populations from northern Spain stands out as distinct on account of both cytogenetic and allozyme analyses.