Motor recovery after unilateral sensorimotor cortex ablation or sham-injury was measured in apolipoprotein E knockout and wild-type mice by testing their abilities to traverse a narrow beam. All mice trained without difficulty. Sham-operated mice performed perfectly regardless of genotype throughout testing. There was no difference in motor scores between lesioned apolipoprotein E knockout and wild-type mice on a first trial 24h after injury (P>0.05). There was a significant overall effect of lesion on motor performance (two-way repeated measures analysis of variance F(1,42)=304, P<0.0001), a significant time effect (F(17,714)=58, P<0.0001) and a lesion by time interaction (F(17,714)=58, P<0.0001). However, there was no effect of apolipoprotein E genotype group on recovery rate (i.e. there was no lesion group by genotype group by time interaction, F(17,714)=0.33, P=1.00) and no effect of genotype on the final level of motor performance 12 days after the lesion (Kruskal-Wallis H=5.79, P=0.12). These data suggest that motor recovery after unilateral injury to the sensorimotor cortex does not vary with apolipoprotein E genotype.