Interactions of species have been recognized to play an important role in the structure and functioning of the environment. However, the exact mechanism is not well understood particularly under shifting environmental conditions like pollution. To determine the effects of pollutants/contaminants on the fitness of two soil nematodes (Acrobeloides nanus and Bursilla monhystera) under pristine and polluted condition, we performed experimental set-ups (monoculture and combined cultures) and exposed the organisms to varying sublethal cadmium (Cd) concentrations (0 mg/L, 1.4 mg/L and 1.9 mg/L). In monoculture, results showed continuous increase in the abundances of A. nanus and B. monhystera in non-polluted condition. Abundance of A. nanus remained increased in polluted condition, however, B. monhystera responded negatively to increasing Cd concentrations. In combination, results in non-polluted condition showed that B. monhystera exhibited a negative effect on the abundance of A. nanus, suggesting that B. monhystera is a stronger competitor than A. nanus. However, a shift in abundance pattern was observed when both species were exposed to pollutants particularly on the positive effect by A. nanus on B. monhystera which implies that sublethal Cd concentrations can potentially alter species interactions. Thorough assessment of nematode interactions is essential in explaining patterns of community structure in disturbed systems and determining proper functioning in the ecosystem.