<p>The emergence or worsening of sexual dysfunction is a frequent consequence of cancer treatment. Our aim was to determine the effectiveness of a psychosexual group intervention in improving sexual interest disorder in female cancer survivors. We carried out an experimental study conducted with a waiting list control group. The sample comprised 63 women (<i>M</i> = 51.49&#xa0;years, <i>SD</i> = 5; range: 35–63). All the participants had been diagnosed with cancer, had had a partner for at least six months prior to starting the intervention, had completed inpatient cancer treatment, and had difficulties with sexual desire that were related to their cancer process. We assessed the presence of sexual interest disorder (DSM-5), levels of dyadic and solitary sexual desire, the effect of the treatment on their relationship, and the credibility of, and satisfaction with, the treatment. The efficacy in improving sexual interest disorder of the psychosexual group intervention administered to a group of female cancer survivors was confirmed. The pre-treatment prevalence of sexual interest disorder was 100% in both groups. The post-treatment prevalence of sexual interest disorder was 96.8% in the control group and 62.5% in the experimental group (<i>p</i> &lt; .001). At 6-month follow-up, the treatment maintained its effectiveness. At the intrasubject level, the data showed statistically significant differences for the number of symptoms from DSM-5 (time: <i>F</i> = 48.31,<i> p</i> &lt; .001) and solitary sexual desire (time:<i> F</i> = 7.78,<i> p</i> &lt; .001). The results may be of significance for the sexual health of women diagnosed with cancer.</p>