To evaluate the psychosocial situation of breast cancer (BC) patients with dependent children, with regard to who used family-centered psychosocial support (PS) services, reasons against using it, as well as existing, unmet needs, and current PS need. Data were collected via survey and patient files during an inpatient rehabilitation program for mothers with BC, who were accompanied by a child <12 years. Descriptive statistics and tests for statistical significance were used. Out of the total of 561 patients, 23.0% had used family-centered PS services before. Common reasons against it were enough support, no anticipated need and organizational issues. Patients stated a high number of unmet needs. The most urgent ones related to their children. About 59.3% of mothers stated a current PS need (PSN) and 33.3% a need for their children. Little social support and a worse maternal HRQOL, but not time since diagnosis, were related to a higher PSN in mothers and children (bivariate association). Among BC patients with dependent children, clinicians need to take the whole family and their support needs into account. They should know about the existing organizational barriers, which need to be overcome with the help of tailored offers. Patients with low HRQOL, little social support and single-mothers (with regard to children's PSN) need special attention as these can be indicators of high PSN.