This paper reports on a Canadian study of the views of 15 women who had altruistically donated oocytes to a friend or a relative for family building and 18 women who had received oocytes donated by a friend or a relative towards disclosure of the donation to both the donor-conceived child and the child(ren) of the donor. Semi-structured interviews were undertaken with participants either in person or by telephone. The vast majority of donors and recipients reported concordance regarding disclosure. There was a greater tendency towards disclosure than for non-disclosure, especially where the donation had resulted in the birth of a child. Nevertheless, participants expressed considerable ambiguity around the optimum time for disclosure. The study highlights unique characteristics in co-ordinating disclosure plans to children in both families when the donors also had young child(ren) and how the relationships between donors and recipients and their families may be expected to impact on, and be impacted by, their disclosure decisions. These include the psychological and social costs that may occur when donors and recipients disagree regarding disclosure. Findings from this study contribute to the currently limited research evidence on disclosure to children in both donor and recipient families following known oocyte donation.