||Interseeding nontraditional, cool-season legumes into bermudagrass [Cynodon dactylon (L.) Pers.] paddocks was evaluated as an approach to increasing the quality and duration of forage production and replacing a portion of the N fertilizer required in the southern Great Plains. We compared the effects of interseeding either grass pea (Lathyrus sativa L. ’AC-Greenfix’) or lentil (Lens culinaris Med. ’Indianhead’) with N fertilizer rates of 0, 45, or 90 kg ha(-1) N. All plots received 60 kg P2O5 ha(-1) in early March. The legume and fertilizer treatments were imposed in mid-March during 2001, 2002, and 2003. Forage samples were clipped from 0.25 m(-2) quadrats on five sampling dates between 1 May and 15 July each year. Yield, N concentration, species composition, and in vitro digestible dry matter (IVDDM) were determined. Year, sampling date, and treatment showed significant (P < 0.05) effects, as did the two-way interactions between all three factors. Total end-of-season standing dry matter of bermudagrass and grass pea was 5550 +/- 423 (SEM) kg ha(-1), which was similar to biomass production with 5 kg ha(-1) N (5305 +/- 570 kg ha(-1)) and less than that produced with 90 kg ha(-1) N (7785 +/- 725 kg ha(-1)). Forage N and IVDDM concentrations for the grass pea treatment were 34 and 6% higher than for bermudagrass, but N and IVDDM concentrations of the forage mixture were intermediate between the higher N rates. Although additional studies are needed to optimize management for the interseeded legumes, we conclude that this practice can improve the quality and duration of bermudagrass forage production in this region.