Setting: The infection with Mycobacterium tuberculosis gives a delayed immune response, measured by the tuberculine skin test. We present a new technique for evaluation based on automatic detection and measurement of skin temperature due to infrared emission.; Design: 34 subjects (46.8+/-16.9 years) (12/22, M/F) with suspected tuberculosis disease were examined with an IR thermal camera, 48h after tuberculin skin injection.; Results: In 20 subjects, IR analysis was positive for tuberculine test. Mean temperature of injection area was higher, around 1 degrees C, for the positive group (36.2+/-1.1 degrees C positive group; 35.1+/-1.6 degrees C negative group, p < 0.02 T test for unpaired groups).; Conclusion: IR image analysis achieves similar estimation of tuberculin reaction as the visual evaluation, based on higher temperature due to increased heat radiation from the skin lesion.