The t(4;14)(p16.3;q32) in multiple myeloma (MM) leads to an apparent deregulation of the FGFR3 and WHSC1/MMSET genes. FGFR3 mutations, known to be associated with genetic skeletal disorders, have also been identified in a few cases of MM (mainly cell lines) with t(4;14). We investigated FGFR3 mutations in a series of 53 MM cases; 11 cases with t(4;14) and FGFR3 overexpression were analysed using reverse transcription polymerase chain reaction, while the remaining cases were studied at DNA level. The Arg248Cys mutation, which is associated with some lethal forms of skeletal disorders, was found in one case with t(4;14). Our results indicate that FGFR3 mutations occur in only a small fraction of MM cases with t(4;14).