Insufficient supply of animal protein is a major problem in developing countries including Nigeria. Rabbits are adjudged to be a convenient source of palatable and nutritious meat, high in protein, and contain low fat and cholesterol. A doe can produce more than 15 times her own weight in offspring in a year. However, its productivity may be limited by inadequate nutrition. The objective of this study was to determine the effect of probiotic (Saccharomyces cerevisiae) supplementation on growth performance and some hematological parameters of rabbit. The appropriate level of the probiotic inclusion for excellent health status and optimum productivity was also determined. A total of 40 male rabbits were randomly divided into four groups (A–D) of ten rabbits each. Each group was subdivided into two replicates of five rabbits each. They were fed pelleted grower mash ad libitum. The feed for groups A to C were supplemented with bioactive yeast (probiotic) at inclusion levels of 0.08, 0.12, and 0.16 g yeast/kg diet, respectively. Group D had no yeast (control). Daily feed intake was determined. The rabbits were weighed weekly. The packed cell volume (PCV), hemoglobin concentration, white blood cell total, and differential counts were determined at the 8th week, 16th week, and 22nd week following standard procedures. The three results which did not have any significant difference were pooled together. Group A which had 0.08 g yeast/kg of diet had a significantly lower (P ≤ 0.05) PCV than groups B (which had 0.12 g yeast/kg of diet) and C (which had 0.16 g yeast/kg of diet) as well as D (the control). Total WBC count for groups B and C (14.35 ± 0.100 × 10³/μl and 14.65 ± 0.786 × 10³/μl, respectively) were significantly higher (P ≤ 0.05) than groups A and D (6.33 ± 0.335 × 10³/μl and 10.40 ± 0.296 × 10³/μl, respectively). Also the absolute neutrophils and lymphocytes counts were significantly higher (P ≤ 0.05) in groups B and C than in groups A and D. Group B had significantly higher (P ≤ 0.05) weight gain (1.025 ± 0.006 kg/rabbit) followed by group A (0.950 ± 0.092 kg/rabbit). The control (group D) had the least weight gain of 0.623 ± 0.0.099 kg/rabbit. These results showed that like most probiotics, bioactive yeast at an appropriate level of inclusion had a significant beneficial effect on health status and growth rate of rabbit. Probiotic supplementation level of 0.12 g yeast/kg of diet was recommended for optimum rabbit production.