Background: The field experiment was conducted to check the optimization of fertilizer requirement for napier grass and cowpea intercropping system at the farm of Lovely Professional University, Phagwara, Punjab during kharif season (2022). Methods: Three replications of factorial RBD design with 4 cropping patterns (I1, I2, I3 and I4) and 3 fertilizer levels (F1, F2 and F3) were set up. Study was conducted on total twelve treatment combinations, I1 (Sole napier with 100, 75 and 125% RDF), I2 (Sole Cowpea with 100, 75 and 125% RDF), I3 (Napier grass+cowpea intercropping in 1:2 ratio with 100, 75 and 125% RDF) and I4 (Napier grass+cowpea intercropping in 1:3 ratio with 100, 75 and 125% RDF). Result: The results showed that in the interaction effect of intercropping and fertilizer levels the the highest value of pH and EC was found to be in I1F2- Sole Napier+75% RDF (8.04 and 0.42 mhos cm-1, respectively). Higher OC was found in I4F3- Napier+cowpea (1:3)+125% RDF (18.23%) as compared to sole napier. However, sole cowpea plots recorded highest OC (18.60 %) in I2F3- Sole Cowpea+125% RDF but lowest pH and EC. The lowest N, Pand K in soil were seen in I1F2- Napier grass+75% RDF (90.00, 10.93 and 124.4 kg ha-1, respectively) in interaction of intercropping and fertilizer levels among treatment combinations of napier grass. I2F3- Sole cowpea+125% RDF recorded (225, 20.68 and 214.93 kg ha-1) N, P and K, respectively, which was highest among all the treatment combinations. Highest net returns and B: C ratio of 3.37 was recorded from intercropping ratio 1:3 and 125% RDF which was followed by 100% RDF (3.13) and 75% RDF (2.77).