The article is devoted to the analysis of the resolution of the Supreme Court of 9 October 2020, III CZP 91/19. The adopted resolution deals with the issue of representation of a minor child by a guardian ad litem in the case of an action for waiver of alimony filed against the minor by the parent to whom the court has granted custody. The author supported the correctness of the Supreme Court's decision presented in the adopted resolution, while drawing attention to the complex nature of the issue itself.