Kenyan landraces of the cultivated white-flowered gourd Lagenaria siceraria have highly variable morphology. In order to reveal the inter- and intra-specific variation in fruit and seed morphology in L. siceraria and its wild relatives in Kenya, various traits were examined in a total of 425 strains from L. siceraria (269), Lagenaria sphaerica (124), Lagenaria abyssinica (27) and Lagenaria breviflora (5). Data analysis revealed the following patterns: (1) L. siceraria is more diverse than its wild relatives in both qualitative and quantitative and fruit traits are more variable than seed traits within each species. (2) Principal component analysis of L. siceraria with 15 quantitative traits showed a continuous variation among strains, in which general size factor of fruit and seed, shape factor of fruit and shape factor of seed were the principal causes of variation. (3) No correlation was found between fruit and seed shape, or between size and shape. (4) Image analysis with elliptic Fourier descriptors revealed continuous shape variation in the landraces of L. siceraria. Fruit shape features such as the contrast between a wide base with a distinct handle, and a slender base with an indistinct handle and the degree of bulge of the elongated handle (bilobate shape) were evaluated quantitatively. (5) Analysis of variance of 12 quantitative traits based on the progeny test demonstrated that the degree of heterozygosity is considerably low in the white-flowered gourd existing in the natural environment in Kenya. (6) The quantitative evaluation of the intra-specific variation in fruit and seed in L. siceraria was possible, but it was difficult to classify the landraces into distinct groups. Most of the variation observed in the cultivated L. siceraria, including differences in fruit size and shape, shell thickness and handle development, probably resulted from selection by the local human population.