The use of core and hammer tests for determining the in-place compressive strength of hardened concrete is studied. The study consulted pertinent literature on both test methods and supported the discussion with actual field data. Although the two methods are applicable for in-place compressive strength determination, they have their own deficiencies. Hammer tests are indirect methods of measuring strength and are very sensitive requiring proper calibration. On the other hand, core tests are direct in-place strength measuring methods where core samples taken from the actual structure are tested in a similar way to test specimens. However, analysis and interpretation of both tests is a tricky business that has to be handled professionally. Before testing is carried out, both hammer and core tests require adequate planning including the methods and criteria for analysis, interpretation, acceptance and rejection.