Objective: To compare glycaemic control and pregnancy outcome in women with type 1 diabetes treated with the long-acting insulin analogues detemir or glargine. Methods: Retrospective study of singleton pregnancies from 2007 to 2011 in women with type 1 diabetes with a single living fetus at 22 weeks using either insulin detemir (n = 67) or glargine (n = 46) from conception. Results: Baseline characteristics were similar in the detemir and glargine groups. Haemoglobin A(1c) was comparable at 8 weeks (median 6.6% (range 5.6-9.8) vs. 6.8% (5.4-10.1), p = 0.15) and at 33 weeks (6.1% (5.1-7.6) vs. 6.2% (4.8-7.2), p = 0.38). The incidence of severe hypoglycaemia was comparable (15 (23%) vs. 10 (23%), p = 0.98). Pre-eclampsia occurred in 9 (14%) vs. 8 (18%), p = 0.52, pre-term delivery in 21 (31%) vs. 16 (35%), (p = 0.70) and 33 (49%) vs. 14 (30%) infants were large for gestational age (p = 0.046). No perinatal deaths were observed. One offspring in each group was born with a major congenital malformation. Conclusions: Glycaemic control and pregnancy outcome were comparable in women using insulin detemir or glargine, except for a lower prevalence of large for gestational age infants in women on glargine. The use of both long-acting insulin analogues during pregnancy seems safe.