Although plasma cell disorders, such as hypergammaglobulinemia and monoclonal gammopathy of undetermined significance (MGUS), are reported to occur at higher incidences in patients with Type I Gaucher disease (GD) than in the normal population, pure light chain multiple myeloma (LCMM) has never been described in this context. Our case is the first to highlight a patient with LCMM who developed clinically apparent GD only following chemotherapy and hematopoietic stem cell transplantation. Renal complications are also exceedingly rare in GD, but nephrotic syndrome is one of the presenting features in this patient. The findings from this case will have important screening and diagnostic implications for both clinicians and patients.