In the article a critical analysis of art. 90 of the Polish Family and Guardianship Code, which deals with the change of a stepchild’s surname, was conducted in the light of Polish and foreign law, and some de lege ferenda conclusions were formulated. Six problematic areas were identified: 1) the absence of a requirement for the second parent’s approval of a surname change, 2) the decoupling of applying for a surname change from the right of ongoing custody over a child, 3) exceptions to the admissibility of surname change separated from real family relations, 4) the untenable ratio legis of art. 90 § 2 of the Family and Guardianship Code derogations, 5) the lack of express time limits for a surname change, and 6) too high age limit for a c...