Tomato is a fruit of great commercial importance and highly cultivated. However, postharvest losses represent one of the main problems of this crop and can be minimized as alternative techniques. Therefore, the objective of the present work was to maintain tomato firmness by applying calcium chloride-associated pectin-methylesterase (PME) by the vacuum infusion method. Tomatoes of cultivar IAP-6 were submitted to vacuum infusion with water, vacuum infusion with 5% calcium chloride and vacuum infusion with PME associated with 5% calcium chloride, fruits without infusion were used as control. Fresh mass loss, fruit firmness, peel color, soluble solids content, pH, total acidity, PME activity and calcium activity were evaluated. The experiment was carried out in a completely randomized design in a 4x5 factorial scheme with three replications for 12 days, evaluated every 3 days. The means were compared using the Tukey test (p <0.05). Data were analyzed graphically with confidence interval (CI p <0.05). Regarding the loss of fresh mass there was an increase over time in all treatments. The PME + CaCl2 5% treatment was the most suitable for reducing firmness loss, as well as presenting the smallest variation of PME activity, as well as low levels of organic acids. Therefore, vacuum infusion with PME + CaCl2 in tomatoes maintains acceptable firmness and physicochemical characteristics as well as CaCl2 infusion.