Developmental delay and intellectual disabilities (DD/ID) are significant health problems affecting 3% of the human population. Submicroscopic chromosomal rearrangements involving subtelomeric regions are often considered to be the cause of unexplained DD/ID. Screening of subtelomeric regions was performed in 80 unrelated patients with DD/ID and normal GTG-banded chromosomes using the MLPA method with two kits (SALSA P070-B1 and P036-E1). The MLPA screening revealed subtelomeric chromosome aberrations in four cases (5%). The aberrations detected were: 1p deletion, 1p deletion combined with 12q duplication, 4p deletion, and 9p deletion combined with 15q duplication. The deletions detected were classified as causative for the patients' observed phenotypes. This study confirms the high frequency of subtelomeric rearrangements in unexplained DD/ID and reinforces the argument for routine subtelomeric screening in order to get a correct diagnosis, establish genotype-phenotype correlations and offer accurate genetic counseling.