This study investigated the effects of two different true-false questions on memory awareness and long-term retention of knowledge. Participants took four subsequent knowledge tests on curriculum learning material that they studied at different retention intervals prior to the start of this study (i.e. prior to the first test). At the first and fourth (pre- and post-) tests, participants indicated which form of memory awareness (i.e. remember, know, familiar and/or guess) accompanied their answer. On the two intermediate tests, testing format was manipulated: true/false or true/false justification, that is a true/false statement with the additional instruction to explain why the statement is true or false. The results resembled earlier findings in that different forms of memory awareness could be distinguished. The study did not indicate (additional) knowledge schematisation as a result of testing or testing format. However, independent of test format, the proportion of correct answers on the post-test was higher than on the pre-test. This could indicate that the beneficial effects of testing can occur even when the learning episode was at a long retention interval prior to the first test.