What is the relationship between the age or gender of the patient and the incidence of fracture-healing complications after internal fixation of intracapsular fractures? We aimed to determine the association between the age of the patient and fracture nonunion and also to establish if the gender of the patient had any influence on the occurrence of fracture nonunion. We prospectively studied 1133 patients with intracapsular fractures of the femoral neck treated by internal fixation. The overall incidence of nonunion was 19.3%. Fracture nonunion was less common for undisplaced fractures than for displaced fractures (48 of 565 [8.5%] versus 171 of 568 [30.1%]) and in men than in women (35 of 271 [12.9%] versus 184 of 862 [21.3%]). The incidence of nonunion progressively increased with age from one of 17 (5.9%) in patients younger than 40 years to 84 of 337 (24.9%) in patients in their 70s. For patients in their 80s, the incidence of nonunion began to decrease, but if patients who died within 1 year after injury were excluded, the incidence continued to increase. Our study showed an increased risk for intracapsular hip fractures developing nonunion with older age and in females.