Phase feeding is employed to optimize lysine levels to meet pigs’ requirements. Therefore, our objective was to evaluate the effect of varying lysine levels and phase lengths in nursery pigs. Four-hundred freshly weaned pigs (5.53 ± 0.96 kg BW) were randomly selected and assigned to 1 of 4 dietary treatments (n = 10 pens/treatment, 10 pigs/pen). The treatments for phase (P) 1-3 were: 1) High synthetic amino acids (1.60, 1.45, 1.33% SID Lys, respectively; HighSyn), 2) High soybean meal (1.60, 1.45, 1.33 % SID Lys, respectively; HighSBM), 3) Low Lys (1.30, 1.50, 1.45% SID Lys, respectively; Low), and 4) Continuous 1.42 % SID Lys (Con). Phase 1, 2 and 3 consisted of 7, 14 and 21 days, respectively. Body weights and feed disappearance were recorded on d 0, 7, 21 and 42, and ADG, ADFI and G:F calculated within phase and overall (0-42 days). All data were analyzed using a complete randomized design with pen as the experimental unit. P1 ADG was 42% higher in the HighSBM compared to the other treatments (P = 0.030), while ADFI tended to be 23% higher (P = 0.089). In P2, ADG was 21% higher in the HighSBM compared to the HighSyn pigs, with the other treatments being intermediate (P = 0.012). ADFI tended to be higher in the HighSBM pigs compared to the other treatments in P2 (P = 0.087). No significant performance differences were reported in P3. Overall, HighSMB had higher ADG compared to Con, Low and HighSyn pigs (0.360, 0.338, 0.338 and 0.311 kg/d, respectively; P = 0.007), while overall ADFI and G:F tended to be lower in HighSyn compared to the other treatments (P < 0.10).