Statistical copolymers of allyl methacrylates with methyl and ethyl methacrylates are synthesized. Moderate conversions are used. Reactivity ratios are calculated by linearised methods which take composition drift into account as well as by non-linear least-squares approximation. For the allyl methacrylate/methyl methacrylate system, r(allyl) values obtained by various methods are between 1,62 and 1,60 and r(methyl) values between 0,36 and 0,34. For the allyl methacrylate/ethyl methacrylate system, r(allyl) values are between 1,37 and 1,16 and r(ethyl) values between 0,40 and 0,47.