Bottle gourd [Lagenaria siceraria (Molina) Standl.] genotypes were collected from different parts of Turkey and a core collection (CC) was established based on morphological characteristics. The collection was grown for morphological characterization and seed multiplication. Seeds were produced from 322 genotypes (Entire Population-EP) representing diversity of entire country by selfing and the accessions were characterized for 25 quantitative and 21 qualitative morphological characteristics. Important variation was observed in fruit size, cotyledon dimensions, leaf dimension, flower size, fruit length (8.7-155.7 cm), fruit shape (flat-elongate), seed weight (3.8 g/100 seeds -38 g/100 seeds) among accessions as previously reported. UPGMA cluster, and principal component analyses cluster of quantitative and qualitative characteristics of EP were assayed. Results of the assays together with geographic origin of the genotypes were analyzed to establish a core population (CC) consisting of 100 genotypes. High correlation between the CC and the EP (r= 0.974 for normalized Mantel Statistic Z) demonstrated that CC represents the most of total genetic variation with minimum redundancy in bottle gourd germplasm of Turkey. The CC will enable efficient and cost-effective management and utilization of bottle gourd germplasm.