A field  experiment  was conducted during rabi  season of  2003-06  to study effect of  irrigation  and nutrient levels with varying crop geometry on growth, yield  and profitability of ajwain (Trichospermi ammi).Three irrigation levels(12,15 and 18 days interval) in main plot, three nutrient levels (N+P2O5 each of 30 + 15 , 40 + 20 and 50 +25  kg /ha, respectively)  in sub plot and three crop geometries ( 40 x 25, 50 x 25 and 60 x 25 cm ) in  sub-sub plot  were studied  in  split- split plot design with three replications. Application of irrigation at 18 days interval  gave  higher yield attributes viz. umbel/plant (184.32), seeds /umbellates(16.97), umbellates/umbel (17.64) , test weight (2.01 g) seed yield (11.69 q/ha), net return (Rs 21885 /ha) and BCR (1.15) over irrigation at 15 and 12 days interval. Significantly higher yield attributes, yield net return of Rs 20320 /ha and BCR (0.97) in ajwain were obtained with application of 50 +25 kg N and 50 kg P2O5 /ha. Crop geometry of 50 x 25 cm resulted 10 per cent higher seed yield over 40 x25 but it was at par with 60 x 25 cm crop geometry. Thus, application of irrigation at 18 days interval with 50+25 kg N and P2 O5 /ha  at 50 x 25 cm crop geometry is better for realizing higher yield, net return  and profitability in ajwain production.