AL amyloidosis patients ineligible for dose‐intensive melphalan (200 mg/m2) were enrolled on a phase II trial to be treated with two cycles of intermediate‐dose melphalan (IDM 100 mg/m2) and mobilized blood stem cells (BSC). For mobilization patients were randomized to either GM‐CSF 250 μg/m2 for 3 d followed by G‐CSF 10 μg/kg for 3 d (GM+G), or G‐CSF 10 μg/kg for 6 d (G‐alone), with leukaphereses on days 5, 6 and 7. To minimize morbidity, we planned to support each cycle with 3.5 × 106 CD34+ cells/kg and had a collection target of 7 × 106 CD34+ cells/kg. Those who did not achieve the target were treated with one cycle of IDM. 30 patients, a median of 62 years old and 7 months from diagnosis, were enrolled. Both mobilization regimens were generally well tolerated, and similar in terms of CD34+ cells and CFU‐GM collected, but only 6/28 patients achieved the collection target (GM+G four, G‐alone two). Despite a 19% incidence of grade 4 toxicities, IDM therapy was well tolerated. At a median follow‐up of 24 months (19–36) 57% of patients had survived, 17% with durable complete haematological responses and 40% with improved or stable amyloid organ involvement, including 3/9 patients with predominant cardiac amyloid who are alive 2–3 years after treatment. The 100 d mortality was 20%. In conclusion, no definitive differences were identified between the mobilization regimens and IDM was an active regimen in AL for selected patients.