Three amino acids (AAs) viz. glycine, L-proline and L- tryptophan plus yeast fungus, Saccharomyces cerevisiae, were tested against root knot disease, RKD, caused by root-knot nematode, Meloidogyne incognita on tomato cv. Super Strain-B. All AAs and yeast showed significant reduction in the number of galls, developmental stages, egg masses and fecundity of the treated plants associated with corresponding positive response in plant growth characters. tryptophan gave significantly higher response in reducing the final nematode population followed by L-proline and glycine at high concentrations compared with yeast and check plants. In most cases, the soil drench application was more effective than foliar spray in reducing nematode build-up. The inhibitory effect of all treatments on nematode reproduction was positively correlated with increasing the concentration used. Plant growth was also promoted by all treatments used. generally, All AAs gave significant impact in suppressing the development of the nematode pathogen and sequentially reliving the disease severity. Results of this research offered environmentally safe approaches for combating root-knot disease. Further researches are needed to determine the proper doses, and concentrations of tested AAs and yeast under semi-field and field conditions. Investigations must include the impact on plant yield, before recommending them for managing root-knot disease or promoting plant growth on a wide scale.