Backgound: Autologous stem cell transplantation (ASCT) is a standard treatment in transplant-eligible mantle cell lymphoma (MCL) patients after first-line chemoimmunotherapy. Study Design and Methods: This prospective multicenter study evaluated the impact of CD34+ cell mobilization and graft cellular composition analyzed by flow cytometry on hematologic recovery and outcome in 42 MCL patients. Results: During CD34+ cell mobilization, a higher blood CD34+ cell count (>30 × 106/L) was associated with improved overall survival (median not reached [NR] vs. 57 months, p = 0.04). The use of plerixafor did not impact outcome. Higher number of viable cryopreserved graft CD34+ cells (>3.0 × 106/kg) was associated with faster platelet (median 11 vs. 15 days, p = 0.03) and neutrophil (median 9 vs. 10 days, p = 0.02) recovery posttransplant. Very low graft CD3+CD8+ cell count (≤10 × 106/kg) correlated with worse progression-free survival (PFS) (HR 4.136, 95% CI 1.547-11.059, p = 0.005). On the other hand, higher absolute lymphocyte count >2.5 × 109/L at 30 days after ASCT (ALC-30) was linked with better PFS (median NR vs. 99 months, p = 0.045) and overall survival (median NR in either group, p = 0.05). Conclusions: Better mobilization capacity and higher graft CD3+CD8+ cell count had a positive prognostic impact in this study, in addition to earlier lymphocyte recovery (ALC-30>2.5 × 106/L). These results need to be validated in another study with a larger patient cohort.