The effect of low concentrations of multifunctional vinyl monomers acting as crosslinking agents, on the properties of poly(styrene-co-n-butyl methacrylates) with 30 % wt of n-butyl methacrylate obtained by solution polymerization at a monomer conversion of approximately 60 wt % has been investigated. Ethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,1,1-trimethylolpropane trimethacrylate and p-divinyl benzene were used as crosslinking agents. The relationship between the gel content, the relative viscosity increment, the weight-average molecular weight, nonuniformity, glass transition temperature, melting volume index and the concentration of the crosslinking agent was determined and discussed.