A cross-sectional study was conducted during the period of August 2007-April 2008 at Al-Wahda Teaching Hospital in Yemen to investigate prevalence and risk factors for placental malaria and anaemia and their effects on birthweight. Sociodemographic characteristics were gathered, maternal haemoglobin was measured and blood films were examined for malaria. Newborn birthweight was recorded. Out of 900 parturient women, malaria blood films were positive in 32 (3.6%) cases: in six sets of peripheral, placental and cord samples; in 15 placental and cord samples; and in 11 placental samples only. Malaria was not associated with age and parity, but it was significantly associated with history of fever [odds ratio (OR) 8.5, 95% CI 3.7-19, P<0.001], rural residence (OR 2.5, 95% CI 1.1-5.3, P=0.01) and rainy season (OR 5.1, 95% CI 1.7-15.2, P=0.003). Overall, 694 (77.1%) out of these 900 women had anaemia (Hb<11g/dl) and 16 (1.8%) patients had severe anaemia (Hb<7g/dl). Anaemia was not associated with age, parity and malaria. Low birthweight was significantly associated with malaria (OR 5.7, 95% CI 1.7-18.5; P=0.004). Thus, preventive measures (bednets and intermittent preventive treatment) should be employed for pregnant women regardless of their age or parity.