Objective: To estimate the differences in albumin levels between donors and recipients with twin-twin transfusion syndrome (TTTS). Methods: We performed a matched case-control study including twin pairs with TTTS treated conservatively (conservative group) or with fetoscopic laser surgery (laser group) and analyzed the albumin levels at birth in donor and recipient twins. Results: We included 18 twin pairs in the conservative group and 36 control twin pairs (laser group), matched for gestational age at birth. Median albumin levels in donor twins in the conservative group were significantly lower than in recipient twins, 25.0 versus 33.0 g/l, respectively (p = 0.001). In the laser group, albumin levels in donors and recipients were similar, 32.0 versus 32.0 g/l, respectively (p = 0.633). Hypoalbuminemia (albumin level