Samples of poly(N-vinyl-2-pyrrolidone (VP)-co-methyl methacrylate (MMA)), containing 41-76.5 wt% MMA, have been prepared by a controlled, semicontinuous copolymerization procedure and swollen to equilibrium in water at various temperatures T (283-343 K) to yield hydrogels in which the network structure is maintained by physical crosslinking involving sequences of MMA units. The effective crosslinking densities (v(e)) and Young’s moduli (E) were determined by compression-strain measurements. Values of v(e) and E decreased with decreasing content of MMA in copolymer, this effect being more pronounced the lower the temperature. For a particular composition, v(e) and E decreased with increasing T to an extent which was greater the higher the MMA content of copolymer. The findings are compared with the behaviour of corresponding chemically crosslinked hydrogels of poly(VP-co-MMA).