OBJECTIVES: X-ray devices are widely available in developing countries but well-disseminated guidelines for their appropriate use are lacking. To help focus behavioral interventions, we determined X-ray utilization rates in different hospital settings and examined the clinical triggers for X-ray requests and the outcomes of X-ray examinations METHODS: Utilization rates were calculated by dividing the total annual number of X-ray examinations with the total annual patient-load. X-ray records were then systematically sampled and data on pre-test clinical impressions and radiologic diagnoses were extracted from them. A total of 15,503 X-ray records in 118 public and private hospitals in Luzon were reviewed. RESULTS: On the average, hospital physicians requested 29 +/- 32 X-ray examinations per 100 hospital patients. X-ray utilization rates tended to be higher in urban (35 +/- 35 per 100 patients) than in rural hospitals (15+/- 18), in private (36 +/- 35) than in government facilities (12 +/- 16) and in tertiary (36 +/- 32) than in primary (29 +/- 37) or secondary hospitals (24 +/- 30). Routine physical check-ups and pre-operative clearances were the most common clinical triggers (24% of X-ray records). Trauma (16%), a diagnosis of pulmonary tuberculosis (11.2%) and cough (10.8%) were the other frequent reasons for ordering X-rays. Among those undergoing routine X-rays, 79% were negative while 7% were positive for PTB. Among those with prior diagnosis of PTB, 42% were confirmed while 28% had negative chest X-rays. Among those with cough, 24% had PTB, 29% had bronchopneumonia and 29% were negative. CONCLUSIONS: Wide variations in X-ray utilization rates exist among different facilities. X-rays frequently confirm the diagnoses of PTB or other pulmonary disorders but are often negative when used routinely.