The age-related changes in the coefficient of microviscosity and polarity in the area of lipid-lipid and protein-lipid contacts of erythrocyte membranes in 4 months old (group I, n = 20) and 12 months old (group II, n = 20) rats by the method of lateral diffusion of the pyrene probe were investigated. Each age group consisted of 10 intact animals and animals after postinfarction cardiac remodeling (PICS). An increase of microviscosity and polarity of the annular and total lipids of erythrocyte membranes in 12-month animals was found. When modeling PICS in 4-month animals is pronounced increase the polarity and microviscosity of erythrocyte membranes in the annular and total lipids. The 12-month animals after PICS demonstrate a decrease of microviscosity in a lipid bilayer, and its increase in the area of annular lipids for consistently high-polarity lipids.