[en] Beta irradiation by Strontium (Sr-90) has been in use for about 20 years in Bangladesh. This retrospective analysis was performed to evaluate its efficacy and the risk and incidence of complications, both short-term and long-term. A retrospective analysis was done of all 417 patients receiving post-operative beta irradiation from January 2001 to January 2006.There were 303 males and 114 females, age ranged from 18 to 65 years with a mean of 38 years. Each patient received 2500cGy to the post-operative sclera surface in five fractions by hand held Sr-90 surface applicator from Amersham International. The patients were followed up at one week, one month, six months and one year after beta irradiation. All 417 cases reported for follow up at one week. But then gradually some patients did not turn up according to the schedule. The number of patients who reported for follow up at one month, 6 months and one year were 401, 325 and 288 respectively. Eighteen cases had recurrence within one year and received a second dose of beta radiation. Short-term complications included conjunctivitis, photophobia, watering of eyes etc. As for long term complications, two patients developed cataract and one patient developed ophthalmomalacia. The short-term complications were self limiting and had no serious effects. The two cases who developed cataracts were over 50 years old, so it could not be clearly understood whether the normal ageing process or the radiation contributed more in the development of the cataract. The rare ophthalmo-malacia developed in a case, which had simultaneous Graves' disease. All other patients in the study are doing well with significant improvement in visual acuity. The results of this retrospective study reveal that Sr- 90 beta irradiation is an effective and safe treatment option to prevent recurrence of Pterygium. (author)