The article deals with tacit acceptance amendment procedure, a legal concept common to the greater number of maritime conventions. In order to speed up adjustment of maritime law to the requirements of present day commerce, especially with respect to technical issues, the International Maritime Organization has introduced a method of amending its conventions by way of a proposal drawn up and adopted by qualified majority voting at I MO institutions. The proposal is then forwarded to the states parties; if a state does not expressly reject the proposal within a fixed period, the amendment is considered to have been accepted by that state and becomes binding as an integral part of the convention. During a working session at Committee for Codification of Maritime Law there was a dispute with Government Legislation Centre regarding methods of introduction of tacit acceptance amendments into Polish law. The author recommends effecting a simplified scheme for introduction of such amendments into Polish legal system and proposes changes to the Maritime Code regarding relations between domestic and international rules of law.