A proportion of patients with multiple myeloma (MM) who have already undergone autologous stem cell transplantation (autoSCT) might benefit from a further transplantation. For this, they might need to undergo another round of stem cell mobilization. We analyzed retrospectively the outcomes of stem cell mobilization with plerixafor and granulocyte colony‐stimulating factor (G‐CSF) in a group of 30 patients who had undergone autoSCT previously, and in 46 other patients. The previously transplanted patients were significantly different from the remaining patients with respect to the intensity and number of previous therapies. We observed that the median peripheral blood concentration of CD34+ cells after the first administration of plerixafor was lower in previously transplanted (19 cells/μL) than in other patients (30 cells/μL, P < 0.05). Despite a comparable number of apheresis sessions being performed, the median total yield of CD34+ cells was significantly lower in the previously transplanted than in the remaining patients (2.8 × 106 cells/kg vs. 4.2 × 106 cells/kg, P < 0.05). However, successful collection of at least 2.0 × 106 CD34+ cells/kg was achieved finally in a similar proportion of previously transplanted and other patients (70% vs. 82.6%). Our data suggest that stem cell mobilization with plerixafor and G‐CSF might overcome the negative effect of prognostic factors for poor stem cell mobilization in patients with MM who have undergone autoSCT previously.