The article presents an evolutionary approach of the Basle Committee for Banking Supervision to measuring banks´ capital adequacy. It has changed considerably since 1988 when a formal construction of commonly applied today solvency ratio was presented. In 1996, principles of capital adequacy measurement were modified by adding market risk to estimated credit risk. Supervisory authorities were aware of the fact that those were not the only risks affecting banks´ situation considerably. In the middle of 1999, a consultation document was presented, in which a new approach to capital adequacy was discusses. The adequacy would base on three pillars: minimum capital requirements, supervisory analysis of capital adequacy, and market discipline. The article also points at consequences related to the adoption of such proposals, and capital adequacy measurement in Poland.