Effects of NPK (15:15:15) fertilizer on some growth indices of pumpkin, Cucurbita moschata (Duch. ex Lam.) Duch. ex Poir. were studied. Eight treatments viz; 0, 200, 250, 300, 350, 400, 450 and 500 kg of NPK fertilizer per hectare (kg ha-1) were used in a Randomized Complete Block Design (RCBD) with four replicates. These treatments were applied once to two week-old seedlings of C. moschata using ring method. The effects of these treatments on Leaf Area (LA), stem diameter (STD) and number of leaves (NL) were monitored weekly while fresh weight and dry weight were determined after 6 weeks. Soil Organic Matter (OM), Organic Carbon (OC), ash content, pH and nutrient (N, P, K, Ca, Na and Mg) levels were also monitored at 0, 2 and 6 weeks. The study showed that NPK fertilizer increased the LA, STD, NL and nutrient (N, P, K, Ca, Na and Mg) contents of the soil. The highest leaf area, stem diameter, fresh weight and dry weight were obtained from NPK treatment at 300 kg ha-1 while 350 kg ha-1 rate gave the highest number of leaves. Two weeks after treatment, the concentrations of N, Ca, Mg, OM and OC content in the soil were highly increased by the 400 kg ha-1 treatment but the 500 kg ha-1 rate gave the highest concentrations of K and Na. The study after six weeks showed that 450 kg ha-1 rate gave the highest concentrations of Ca, Mg and K in the soil whereas 500 kg ha-1 rate gave the highest concentrations of P, Na and ash content. The 350 kg ha-1 gave the highest N, OM and OC content. At p<0.05, there were significant difference among treatments. The use of NPK fertilizer at an application range between 400 and 450 kg NPK ha-1 is therefore recommended for growing of C. moschata and improvement of the soil nutrients level.