Cassava is an important food energy source in tropical and subtropical regions. There have been successful efforts to increase the β-carotene content in cassava through biofortification. However, the bioefficacy of the β-carotene in the biofortified cassava in humans has not been studied. In the present study, we investigated the bioefficacy of the β-carotene in biofortified cassava in 9 healthy women ages 18-39 y. After eating conventional foods with low β-carotene and vitamin A contents for three days, the subjects were asked to ingest one of the three cassava porridges in random order. All of the porridge servings were about 200 g and contained 40 g cassava flour. The three porridges included biofortified cassava porridge (1097.5 μg β-carotene), white cassava porridge with vitamin A reference dose (285.6 μg retinol) and white cassava porridge with β-carotene reference dose (537.6 μg β-carotene). Blood samples were collected prior to ingestion of the test porridge and at 2, 3.5, 5, 6.5, 9 hours after ingestion. Plasma triacylglycerol rich lipoproteins (chylomicrons and large VLDL) were isolated and the retinyl palmitate contents were analyzed by HPLC-ECD. The mean amounts of retinyl palmitate appearing in the triacylglycerol-rich lipoprotein fraction in the entire plasma pool after ingestion of the biofortified cassava porridge and the white cassava porridge with the β-carotene reference dose were 1587.53 ± 285.27 and 914.35 ± 128.50 nmol. The vitamin A equivalence values of the β-carotene in these two porridges were 2.80 ± 1.77 to 1 and 2.11 ± 0.81 to 1 (by weight), respectively. These vitamin A equivalence values were not significantly different by t test. In our study population, the bioefficacy of the β-carotene in biofortified cassava was as good as that of a β-carotene supplement.