Brisket disease in cattle is the most important limit for stockbreeding at the Peruvian mountains. There are many factors involved and being race cattle's more susceptible to present this disease. The hematology values are the first in change when the animals are exposed to high altitude hypoxia. The purpose of this study was evaluate the altitude hypoxia effect over hematology values of 10 male, 1 to 2 months age, jersey bovines, were born at sea level (SL), Lima, Perú, and exposed to 3320 m of altitude (Middle mountains from Perú). The hematology values evaluated were Hematocrit (HCT) (%), Hemoglobin concentration (HGB) (g/dl), Red cells count (RBC), Mean corpuscular volume (MCV) (μm3), Mean corpuscular hemoglobin (MCH) (ρg) and Mean corpuscular hemoglobin concentration (MCHC) (g/dl) at SL, 3 (T1) and 30 (T2) days of exposition to high altitude. The average results obtained were: HCT at SL: 27.64±4.54 and 30.09±3.62 (T1) and 38.90±3.70 (T2), being different (p<0.05) to 30 day. HGB values were 8.19±1.44 at SL and 10.52±1.43 (T1) and 13.84±1.28 (T2), being different between 3 groups (p<0.05). RBC (x106/μl) at SL 7.82±2.32 and 8.67±1.96 (T1), 10.31±1.15 (T2), being different between SL and T2 (p<0.05). MCV was 37.29±8.69 at SL and 35.69±5.93 (T1), 38.11±5.24 (T2). MCH at SL was 11.03±2.58 and 12.47±2.21 (T1), 13.59±2.21 (T2). MCHC: 29.66±2.19 at SL and 34.92±1.63 (T1), 35.64±1.88 (T2). We conclude that time of exposition to high altitude hypoxia until 30 days increased (p<0.05) HCT, HGB, RBC, MCH and MCHC values in Jersey cattle.