The purpose of this study was to analyze the geometry of the primary cleft lip nasal deformity using three-dimensional computerized tomography in a group of 3-month-old infants with complete unilateral cleft lip and palate before surgical intervention. Coordinates and axes were reconfigured after the three-dimensional image was oriented into neutral position (Frankfurt horizontal, true anteroposterior, and vertical midline). Display and measurement of skin surface and osseous tissues were achieved by adjusting the computed tomographic thresholds. S-N, N-ANS, S-N-O, and S-N-ANS were measured from true lateral views. Biorbital (LO-LO), interorbital (MO-MO), intercanthal (en-en), and nasal (al-al) widths were measured from the anteroposterior view. The bony alveolar cleft width was measured from the inferior view. The study group was divided into two groups on the basis of skeletal alveolar cleft width: six patients with clefts narrower than 10 mm and six patients with clefts wider than 10 mm. Only the S-N-ANS angle differed between the two groups, i.e., it was greater in the group with the wider clefts (p < 0.05). Coordinates of six landmarks at the base of the nose [sellion (se), subnasale (sn), cleft-side and noncleft-side subalare (sbal-cl and sbal-ncl), and the most posterior point on the lateral piriform margins (PPA-CL and PPA-NCL)] were obtained for analysis of the nasal deformity. On average, the subnasale point was anterior to sellion and deviated to the noncleft side; the cleft-side sbal point was more medial, posterior, and inferior than the noncleft-side sbal point; and the PPA point on the cleft-side piriform margin was more lateral, posterior, and inferior than the PPA point on the noncleft side. These discrepancies were not universally observed. However, in all patients, four findings were observed without exception (p < 0.01): (1) subnasale (sn) was deviated to the noncleft side (mean distance from midline, 5.0 mm; range, 2 to 9.5 mm), (2) the cleft-side alar base (sbal-cl) was more posterior than the noncleft-side alar base (sbal-ncl) (mean difference, 3.6 mm; range, 1 to 5.5 mm), (3) the noncleft-side alar base (sbal-ncl) was further from the midline than the cleft-side alar base (sbal-cl) (mean difference in lateral distances of sbal-ncl and sbal-cl from the midline, 2.8 mm; range, 0.5 to 7 mm), and (4) the cleft-side piriform margin (PPA-CL) was more posterior than the noncleft side piriform margin (PPA-NCL) (mean difference, 2.1 mm; range, 0.5 to 4 mm). In conclusion, the nasal deformity in unilateral cleft lip and palate that has not been operated on is characterized by these four features and increased S-N-ANS angle with increased alveolar cleft width.