The research on the effect of guided imagery (GI) on immune system is reviewed and, accordingly, a direction for future research is proposed. Studies suggest that: GI can reduce stress and elevate the immune system; cell-specific imagery affects corresponding WBCs, neutrophils, or lymphocytes; decreases in WBC count occur in the initial stages of GI and relaxation due to fluctuations in WBC production or margination; and changes in WBC count or adherence occur earlier in medical patients. Directions for further investigations: Definition of the ideal WBC count; the effects of long-term practice of GI; and influence of cell-specific imagery on WBCs.