The aim of the study was to investigate the dynamics of metacognitive monitoring during learning category structures defined by logical rules of different levels of complexity: conjunctive, conjunctive-disjunctive or complex rule. Feeling-of-warmth judgments were used repeatedly during learning to assess participants' subjective feelings about how close they are to the acquisition of the appropriate rule. After each judgment, participants were asked to describe logical rules underlying category structures. As expected, the results showed that feeling-of-warmth judgments generally follow classification accuracy through the course of learning. Rule description accuracy shows a similar pattern and is also congruent with classification accuracy through the course of learning. Contrary to expectations, there were no differences between different levels of category structure complexity on any of the tested measures.