The reactivity ratios of N-vinylcarbazole (r(1)) and N,N-dimethylaminoethyl methacrylate (r(2)) were determined at 60 degrees C in toluene, dioxane, methylethyl ketone and N,N-dimethylformamide (DMF) solutions. The values calculated by the extended Kelen-Tudos method were r(1) = 0.44 +/- 0.05, r(2) = 1.63 +/- 0.10 (in toluene), r(1) = 0.32 +/- 0.05, r(2) = 1.34 +/- 0.10 (in dioxane), r(1) = 0.15 +/- 0.03, r(2) = 1.10 +/- 0.07 (in methylethyl ketone) and r(1) = 0.10 +/- 0.02, r(2) = 0.88 +/- 0.04 (in DMF). There is a marked effect of solvent on both r(1) and r(2) in all these systems, which is most probably due to changes in the dielectric constant of the solvents used.