Pigeonpea (Cajanus cajan (L.) Millspaugh) is an important pulse crop grown by smallholder farmers in the semi-arid tropics. Most of the pigeonpea cultivars grown to date are selections from the landraces, with a narrow genetic base. With the expansion of the crop to newer areas, problems of local importance are to be addressed. Hence, an economically feasible and faster germplasm evaluation mechanism is required. A core collection, which serves as an efficient mechanism was developed from 12,153 pigeonpea accessions collected from 56 countries and maintained at ICRISAT, Patancheru, India. The accessions were placed under 14 clusters based primarily on geographic origin. Data on 14 qualitative morphological traits were used for cluster formation by Ward's method. From each cluster 10% accessions were randomly selected to constitute a core collection comprising 1290 accessions click here to search the data. to view the list of accessions and their Country of origin. Mean comparisons using Newman–Keuls test, variance comparisons by Levene's test, and comparison of frequency distribution by X2 -test indicated that the core collection was similar to that of the entire collection for various traits and the genetic variability available in the entire collection is preserved in the core collection. The Shannon–Weaver diversity index for different traits was also similar for both entire and core collection. All the important phenotypic associations between different traits available in the entire collection were preserved in the core collection. The core collection constituted in the present study facilitates identification of useful traits economically and expeditiously for use in pigeonpea improvement and in selecting varieties suitable for diverse uses.