Chronic hypoxia (CH)-induced pulmonary hypertension may influence basal endothelial cell (EC) intracellular Ca²⁺ concentration ([Ca²⁺]_i). We hypothesized that CH decreases EC [Ca²⁺]_i associated with membrane depolarization and reduced Ca²⁺ entry. To test this hypothesis, we assessed 1) basal endothelial Ca²⁺ in pressurized pulmonary arteries and freshly isolated ECs, 2) EC membrane potential (E_m), 3) store-operated Ca²⁺ current (I_SOC) and 4) store-operated Ca²⁺ (SOC) entry in arteries from control and CH rats. We found that basal EC Ca²⁺ was significantly lower in pressurized pulmonary arteries and freshly isolated ECs from CH rats compared to controls. Similarly, ECs in intact arteries from CH rats were depolarized compared to controls, although no differences were observed between groups in isolated cells. I_SOC activation by 1 µM thapsigargin (TG) displayed diminished inward current and a reversal potential (E_rev) closer to 0 mV in cells from CH rats compared to controls. In addition, SOC entry determined by fura-2 fluorescence and Mn²⁺ quenching revealed a parallel reduction in Ca²⁺ entry following CH. We conclude that differences in the magnitude of SOC entry exist between freshly dispersed ECs from CH and control rats and correlates with the decrease in basal EC [Ca²⁺]_i. In contrast, basal EC Ca²⁺ influx is unaffected and membrane depolarization is limited to intact arteries suggesting that Em may not play a major role in determining basal EC [Ca²⁺]_i following CH.