A Phase 2, single-center, open-label study to assess the safety and hematological activity of plerixafor in patients with non-Hodgkin's lymphoma (NHL) or multiple myeloma (MM) who were predicted to be unable to mobilize ≥2*10^6 CD34+ cells/kg within 3 apheresis days. The only change to the standard of care was the addition of plerixafor to a G-CSF mobilization regimen on the day prior to apheresis.