We studied geographical body-size variation and sexual size dimorphism in three isolated populations of the bush-cricket Pholidoptera frivaldskyi in Central Europe (Slovakia). We measured six body traits in females and seven in males, from 93 individuals (46 males and 47 females): lengths of body, right hind femur, right hind tibia, pronotum, right cercus or ovipositor, length of wing (only in males) and body weight. Not all linear traits in both sexes were correlated with body weight. Generally, females were significantly bigger than males in all parameters. Although discriminant function analysis indicated some significant differences in male traits, there were no strong morphological difference among local populations. Morphological variability among the three populations was not higher than that within populations. This relative somatic uniformity should be verified on the level of genetic variability of the studied populations, since cryptic species diversity can be expected.