The tuberculin tine test, a multiple-puncture intradermal skin test, has been compared with PPD-S, intermediate strength (5 TU (toxic units)), in 976 patients hospitalized for a variety of reasons. All data were submitted for biostatistical analysis. A close concordance was seen for the tine test of 3 mm + (or 2 mm +) with PPD-S of 6 mm +. A less good concordance of the tine test of 6 mm + with a PPD-S of 10 mm + of induration was noted. A minimal positive tine test has been shown to be 3 mm (or 2 mm) or more of palpable induration, correlating best with a PPD-S test of 6 mm or more, defined in this study as a minimal positive PPD-S test. Reading the tests on only the third day, (72 hours after administering the tests) proved best for both PPD-S, 6 mm + and the tine test, 3 mm + or 2 mm +. This was indicated by the presence of the fewest positives "missed" on the third day. Testing PPD-S against PPD-S and tine against tine, each done simultaneously on both arms, it was revealed that: 6% of the PPD tests were "positive " in one arm and "negative " in the other arm at 6 mm or more of induration; and 10% of the tine tests were "positive" in one arm and "negative " in the other at both 2 mm and 3 mm of induration. The tuberculin tine test, a self-sufficient, disposable, plastic unit, easily administered and easily read, should be particularly useful as a tuberculosis case-finding skin test in mass survey work, in office practice, and in home contact testing. The apparent quantitative correlation of the tine test with PPD-S enhances its usefulness. The tuberculin tine test does not detract, however, from the potential accuracy of the international standard PPD-S Mantoux test in the latter''s differential diagnostic usefulness with its three measured dilutions: first, intermediate, and second strengths. The tuberculin tine test should be regarded as a very useful and important addition to our tuberculosis case-finding armamentarium.