This paper discusses the various forms of altered fractionated radiation therapy programmes which were used in the past and at present. Treatment programmes employing large fraction sizes and prolonged treatment course result in severe late complication of the normal tissues and inferior local tumour control respectively, and are no longer advised. The current radiobiologic concepts of altered fractionationated treatment are briefly discussed. The experiences of using accelerated hyperfractionated radiation therapy programme for the treatment of oropharyngeal and laryngeal carcinomas at the Massachusetts General Hospital (MGH) from 1979 through 1994 are presented. The programme consists of 1.6 Gy/f twice-daily (BID) for approximately 67.2-70.4 Gy in 6 weeks with a short 'break' after the initial 38.4 Gy. The local control and disease specific survival rates after BID are reported related to the various stages of the lesions and compared with historical control of once-daily (QD) radiation therapy at the MGH. The data thus far indicated higher local control and disease specific survival after BID radiation therapy for advanced carcinomas (T2-3 lesions). The therapeutic gains, however, did not occur significantly for early lesions (T1 disease). The importance of the effects of the total doses and total treatment time, related to the treatment outcome, is discussed.