Abstract This work describes changes in abscisic acid (ABA) content, membrane permeability, microviscosity, and lipid composition during storage of green and red bell pepper fruit (Capsicum annuum L. cv. Maor). Membrane permeability increased as measured by leakage of electrolytes and ninhydrin-reacting substances, sucb as amino acids. Membrane microviscosity increased initially and then showed a slow decrease. In red peppers, the increase in microviscosity occurred sooner than in green peppers, and the membrane leakage was higher. Examination of the composition of sterol and phospholipid in microsomal membranes revealed a connection between sterol level and membrane microviscosity. Sterol levels increased and then slightly decreased, while phospholipid levels showed no significant change. Abscisic acid levels showed an increase during senescence, followed by a decrease that was more dramatic in green pepper.