Female eastern spruce budworm, Choristoneura fumiferana (Clemens), inoculated sublethally as fourth or fifth instars with Nosema fumiferanae (Thomson), exhibited significant reductions in size, fecundity, and total egg complement. Mating success and egg fertility were similar for treated and control insects. The presence of disease improved the positive correlation between fecundity or total egg complement and female pupal weight without significantly reducing the slope. Toyal egg complement was negatively correlated with disease load. A subsample of progeny reared from each fertile mating indicates 100% transovarial transmission efficiency at the spore dosages provided. Diseased progeny experienced twice the larval mortality, and surviving individuals were approximately 25% smaller and took 17% longer to complete development than healthy progeny. Material disease laod was a significant, positive factor in percentage progeny mortality and male pupal weight.