Early absolute lymphocyte count (ALC) has become an important end point for engraftment in patients undergoing autologous peripheral stem cell transplantation (APSCT). In this retrospective study, we evaluate the prognostic significance of early recovery of ALC ( > or = 0.5 cells x 10(9)/l on or before day 15) following APSCT in predicting transplant outcome in 72 patients with lymphoproliferative disorders, including non-Hodgkin's lymphoma (n = 30), Hodgkin's lymphoma (n = 8) and multiple myeloma (n = 34). The median quantities of CD34+ stem cells and lymphocytes infused were 4.97 x 10(6)/kg (range 0.64-11.7) and 11.3 x 10(7)/kg (range 1.11-110) respectively. After a median follow-up of 18 months (range 2-68), 28 patients had experienced a relapse and 16 had died. Of the 72 patients, 27 (37%) demonstrated early recovery of ALC. Early recovery of ALC was strongly associated with long-term overall and disease-free survival in patients aged less than 50 years (P < 0.001). In both univariate and multivariate survival analyses, a shorter time from diagnosis to APSCT was associated with early recovery of ALC (P = 0.03). These findings indicate that early recovery of ALC may contribute to longer survival in younger patients with lymphoproliferative disorders. A shorter time from diagnosis to APSCT may favor recovery of ALC independent of the infused stem cell or lymphocyte doses.