Autologous hematopoietic cell transplant (HCT) is frequently used to treat Multiple Myeloma (MM). Metabolic abnormalities have been reported in patients (pts) undergoing this modality of therapy contributing to catheter requirement and prolonged hospital admission. Incidence and timing of electrolyte imbalances have not thoroughly been investigated. Methods All consecutive MM pts underwent autologous stem cell transplant from Jan 2012 to July 2016 were included. Patient charts were reviewed for the laboratory results of the first four weeks following HCT. Calcium level was corrected for the albumin level. Time to nadir of these abnormalities was recorded as days after stem cell infusion. engraftment speed (ES) was calculated as the period between the first rise in absolute neutrophil count (ANC) and the full engraftment defined as the first day of ANC>500 for three consecutive days. To define impact of oral intake on the electrolyte drop we assess degree of oral mucositis and nauseas using CTCAE v4.0. Results The study included 118 MM pts received transplant. Median age was 60.9 years old (range: 34-78), 65 pts were male (55%) and the rest female. Ninety pts were Caucasian (76%) and 20 were African-American (19%). Eighty two pts had IgG (69%), 24 IgA (21%) and 11 (9%) had light chain myeloma. Sixty pts (51%) achieved Very Good Partial Response, 29 pts (24%) Partial Response and 25 pts (21%) Complete Response before HCT. Twenty pts (22%) were on Lasix, 62 pts (52%) were on PPI, 3 pts (2%) on H2 blocker at the time of HCT. Conditioning regimen included Melphalan 200 and 140 mg/m2 in 108 pts (91%) and 10 pts (9%), respectively, with pre-melphalan amifostine infusion for all pts. Filgrastim daily started on the day after stem cell infusion. The pre-SCT and post-SCT nadir values are listed in Table-1. Median ES was 2 days (range: 0-5) and 40 pts (36%) had ES Conclusion Here we defined a correlation between magnitude of the drop in potassium and phosphorous and a steep rise in neutrophil counts around the engraftment period. It can indicate the genesis syndrome, a massive transfer of electrolytes into rapidly proliferating cells that was described in high grade lymphoma and leukemia before.