The nematicidal activity of acetyl salicylic acid (ASA) was investigated against root-knot nematode (Meloidogyne incognita) under laboratory and greenhouse conditions. The results of the laboratory experiment showed that ASA exhibited nematicdal activity against 2^nd stage juveniles of nematode with a LC₅₀ value of 150.43 ppm. In the greenhouse experiment, the effect of ASA at three concentrations was tested against root-knot nematode on tomato plants in comparison with oxamyl nematicide as standard treatment. All plants were examined to assess disease severity based on the number of galls per root, egg masses per root, developmental stage within the root system, and average of eggs number per egg mass as well as plant growth characteristics were estimated. The results showed that all tested treatments reduced tomato root galling significantly compared with the untreated treatment. The numbers of galls/root system were (6.33, 12.67, 18.67, and 28.67) for the treatments of oxamyl and 300, 200 and 100 ppm of ASA, respectively, compared with  the untreated check (113) and the other parameter were in the same trend. All treatments increased shoot and root weights and lengths compared with the untreated check. In conclusion, ASA has nematicidal activity to suppress root-knot nematode infection in tomato plants. Thus, this approach could be a safe alternative to use chemical nematicides for the management of plant-parasitic nematodes.