Conflicting results of interaction between selenium (Se) and phosphorus (P) have been reported. Hence, a 3 x 4 factorial randomized complete block design with 3 rates of P fertilizer and 4 rates of Se was conducted under a glasshouse condition to determine the effect of P in soil on Se accumulation in local green spinach (Amaranthus spp.). There were 12 treatments in total and each treatment was replicated three times. Green spinach was grown in pot containing sandy clay soil and applied with Se at rates 0, 60, 120 and 180 g/ha as sodium selenite. Phosphorus fertilizer was applied at 0, 50 and 100% from the recommended amount (23 kg/ha P₂O₅) as diammonium phosphate (DAP). Meanwhile, nitrogen and potassium fertilizer were uniformly given to each pot at 100 kg/ha N and 144 kg/ha K₂O, in the form of urea and muriate of potash (MOP), respectively. The amount of urea was added after taking into consideration of the amount of nitrogen present in DAP. Results from this study show that dry matter of green spinach is affected by the P rates at different level of Se rates. Highest dry matter was obtained when Se was applied at 120 g/ha with 100% of P fertilizer. Reducing P fertilizer into 0 and 50% had reduced the dry matter of spinach and it can be seen when 60 and 120 g/ha Se were applied. In terms of Se accumulation, spinach leaves accumulated higher Se followed by stems and roots. Selenium uptake by leaves and stems of green spinach is affected by the P fertilizer rates at different level of Se rates. In leaves and stems, the highest uptake was observed when 120 g/ha Se with 100% of P fertilizer were applied. However, at 120 g/ha Se, reducing P fertilizer into 50% and 0% had no effect on the uptake of Se by spinach’s leaves and stems, respectively. Meanwhile, Se intake in roots was not affected by the P fertilizer at different level of Se rates. At various P rates, no significant difference were observed in Se intake by roots. Whereas, higher Se uptake by roots was observed when 120 & 180 g/ha Se were applied. Earlier studies indicated that P could reduce the uptake and accumulation of Se in plants. However, antagonistic effect of P fertilizer addition on Se uptake by spinach leaves was observed only at higher Se rate of 180 g/ha Se. According to Liu et al. (2004), when the P supply meet the needs of plant growth, it could promote accumulation of selenium in the shoots. The presence of P also could decrease Se sorption on soil surface and increase the Se concentration in the soil solution. Carter et al (1972) also mentioned that the P application may have stimulated plants to absorb more Se because of increased in root proliferation. In conclusion, although earlier studies pointed out that P could reduce Se uptake by plants, contradictory results were obtained from this study. Applying P fertilizer as recommended could increase yield as well as the Se uptake by leaves and stems of spinach Selenium at 120 g/ha applied to sandy clay soil can be considered as the optimum rate as higher rates could reduce plant yield and decrease the Se uptake by spinach.