Background: The little research there is about suicidal behaviour in those with gender dysphoria indicates that they are at a much higher risk of death by suicide and suicidal behaviour than the general population. The objective of this research is to analyse the prevalence of suicidal ideation and suicide attempts reported by people who attended consultations at the Gender Identity Treatment Unit between 2007 and 2017 presenting complaints related to gender dysphoria. Method: An ex-post facto study with a sample of 151 people who were clients at the unit, 97 in the male to female trans group, 54 female to male. Clinical evaluations were carried out assessing variables of suicidal ideation and attempts, along with a possible psychiatric diagnosis. Results: Almost half (48.3%) reported suicidal ideation, 23.8% had attempted suicide. Conclusions: There are higher levels of suicidal ideation and suicide attempts in people with gender dysphoria than in the general population. No differences were seen between groups in terms of gender/sex. Psychiatric morbidity was not an influential variable for suicidal behaviour. This suggests that suicidal ideation is one of the best indicators of the risk of suicidal behaviours.