Sixty accessions of Yam Bean [Pachyrhizus erosus (L.) Urban) were tested in yield trials during 1992, 1993, and 1994. Significant differences were detected among the years and accessions with the highest yields were recorded in 1992. Some accessions showed yield stability and were high-yielding in all three years. The number of tubers developed per plant was constant for accessions over the years, although some accessions had a greater tendency to form multi-tuberous roots compared with other accessions. There was a highly significant correlation between the number of tubers developed per plant and the total yield. Among the 20 highest-yielding accessions, yield varied between 77.0 t and 125.9 t ha-1. The accessions representing wild genotypes had the highest dry matter (DM) contents of tubers. A significantly negative correlation existed between tuber weight and DM content, while soluble solids content was positively correlated with the DM contents.