Cubitus varus following paediatric supra-condylar humeral fracture represents a complex three-dimensional malunion. This affects cosmesis, function and subsequent distal humeral fracture risk. Operative correction is however difficult with high complication rates. We present the 40-year Yorkhill experience of managing this deformity. From a total of 3220 supracondylar humeral fractures, 40 cases of post-traumatic cubitus varus were identified. There were ten undisplaced fractures, treated in cast, and thirty displaced fractures. Five were treated in cast, thirteen manipulated (MUA), four MUA+k-wires, seven ORIF (six k-wire, one steinman pin) and one in skeletal-traction. Sixteen malunions were treated operatively. The mean pre-operative varus was 19°. All had cosmetic concerns, three mild pain, one paraesthesia/weakness and three reduced movement (ROM). The operative indication was cosmetic in fifteen and functional in one (concern about instability). Twelve patients had lateral closing-wedge osteotomies; three complex/3D osteotomies (dome, unspecified rotational, antero-lateral wedge) and two had attempted 8-plate guided-growth correction. Complications occurred in eight patients (50 %): Fixation was lost in three (two staples, one k-wiring), incomplete correction in six (both 8-plates, both staples, two standard plates) and one early wound infection requiring metalwork removal resulting in deformity recurrence. One patient underwent revision lateral wedge osteotomy with full deformity correction but marked ROM restriction (20–100°) secondary to loose bodies. Those without complications were satisfied (50 %). All patients with residual deformity were unsatisfied. 1 patient with keloid scarring was unsatisfied despite deformity correction. Varus malunion is uncommon (1 %) but needs to be guarded against. It tended to occur in displaced fractures treated with MUA and cast alone. We therefore recommend additional pin fixation in all displaced fractures. Deformity correction should only be attempted in those with significant symptomatic deformity due to the high complication/dissatisfaction rates. Staple osteotomy fixation and 8-plate guided growth correction are not recommended