The lives of people with borderline intellectual functioning (BIF) were retrospectively examined with a population-based sample (N = 416,973), ‘Finland-in-Miniature’. Results were compared to those of the general population, to people with mild intellectual disability (MID), and people with learning problems (LP). Results showed that people with BIF had fewer partnerships, lesser employment, and fewer cases of completing secondary school education than peers in general population. They also had higher rates of unemployment and disability pensions. Regarding family, education, and work, people with MID showed lower rates, and those with LP showed higher rates, than people with BIF. It was concluded that people with BIF are more vulnerable than their peers in the general population regarding partnership, education, and work. It is essential that society supports employment for people with BIF. Retrospective utilisation of existing databases is proposed as a promising method of research to widening an understanding of BIF.