Abstract: Dry matter production and its partition are the best measure and index of the total performance and response of a crop to growth conditions. Two-season experiment was conducted in soil with low available phosphorus (P) to study dry matter production and partitioning among the cowpea plant as influenced by either variety or phosphorus application using triple super phosphate (46% P2O5). In the present study IT89KD-347-57 consistently produced the highest number of leaves. The number of leaves per plant did not differ significantly (p>0.05) with phosphorus application; however, 60 kg ha–1 rate consistently yielded the greatest number of leaves. Asomdwee and Asetenapa recorded the highest and lowest leaf area of 1731.22 and 769.27 cm2, respectively. Leaf area also increased consistently with P application, with 20 kg ha–1 been the optimal rate for greater leaf area. However, leaf area did not differ significantly (p>0.05) with P application. Net assimilation rate was not significantly influenced by P and therefore, 0 kg ha–1 rate yielded the highest NAR. Dry matter production increased with age of plant regardless of the levels of P applied, with 60 kg ha–1 yielding the mean highest value. Dry matter accumulation in the stem was consistently higher than the remaining plant parts regardless of the levels of P applied. However, dry matter production and partitioning among above ground parts were significantly (p<0.05) affected by cowpea variety but not P application. The results in this study indicate that dry matter production among cowpea is totally dependent on varietal differences but not phosphorus application.