Shoot regeneration on cotyledon or hypocotyl explants excised from tomato seedlings and obtained from seeds germinated on MS medium without growth regulators was used to establish tomato shoot culture. Tomato regeneration was influenced by the physiological condition of the donor of explants as well as the explants type. Comparison between the morphogenesis type, SDS and native PAGEs indicated that gene expression can be used to differentiate between tomato cultivars and early determination of the differentiation type, where conditions stimulated shoot organogenesis increased the number and/or the staining intensity of peroxidase and indophenol oxidase bands as well as induced the expression of specific polypeptides. Shoot cultures were used to study gene expression under the influence of stress conditions. Increase in isoenzyme activity under the influence of relatively high concentration of NaCl, manniol or cupper CuSO4 as well as high temperature treatment resulted from increase the number of isoenzyme forms and/or increase the staining intensity of some isoenzyme forms. SDS PAGEs indicated that stress conditions caused an induction or inhibition of the synthesis of some polypeptides. Shoot culture established ideal condition to study gene expression under the influence of biotic and abiotic stress factors in tomato.