Hearing loss was studied in 22 patients with Pierre Robin syndrome (PRS) aged three to 12 years (median 5.0 years). The results were compared to those obtained in 62 patients with isolated cleft palate (ICP) aged one to 27 years (median 5.5 years). Hearing loss was more frequently found in PRS (73.3 per cent) than in ICP (58.1 per cent) patients (p = 0.02). PRS patients had more ears with moderate (21–40 dB) and severe (>40 dB) hearing loss, disturbing their social contact, with no tendency to normalization with age (Spearman r = 0.065). In contrast to PRS, ICP patients showed a significant tendency to hearing level normalization with ageing (Spearman r = −0.453; p = 0.001). Planigraphs of temporal bones showed inadequately developed pneumatization of the mastoid bone in all PRS patients and in most ICP patients. No malformation of the inner or middle ear was found in either group. PRS patients have a significantly higher risk of conductive hearing loss than those with ICP. Use of tympanostomy (ventilation) tubes is therapy of choice in patients with Pierre Robin syndrome, and it should be introduced as early as possible, even at the same time as palatoplasty.