Polyethylene glycol (PEG) is a high molecular weight osmoticum, which can be used to induce water stress artificially in a nutrient medium. An experiment was conducted with four concentrations of polyethylene glycol namely 30 g/L, 60 g/L, 90 g/L with a control to study the effect of PEG on seed germination and seedling performance of tomato cv. KC-1. The experiment was laid out on a complete randomized design (CRD) with six replicates. Data was analyzed using the regression and Pearson correlation analysis. The PEG concentrations fortified to the culture media had significant negative relationships (p<0.0001) for all estimated parameters such as shoot length, root length, fresh weight, dry weight, chlorophyll a, chlorophyll b, total chlorophyll content of the in vitro grown tomato seedlings. The MS media fortified with 0 mg/L PEG treatment (control) exhibited better seed germination percentage (87.8%) and seedling performance, while the minimum value of seed germination (21.9%) was noted under 90 g/L PEG treatment at 20 days after culture. In control PEG treatment, high values were noted for shoot length (2.88 cm), root length (1.67 cm), fresh weight (60.37 mg), dry weight (8.93 mg), chlorophyll a (1.38 mg/g), chlorophyll b (0.48 mg/g), total chlorophyll content (1.86 mg/g) after 4 weeks of culture. The decreased in seed germination and seedling growth rate probably due to lower the water potential of the culture media by supplement with the PEG into the MS medium fortified with 2 mg/L BAP. In vitro germination and seedling growth were considerably reduced on 60 g/L and 90 g/L PEG concentrations.