Abstract: The aim of the study is to determine birth weights, placental weight and Placental to Birth Weight Percentages (PBWP) in consecutive, live singleton term births and study their relationship with some maternal and foetal factors. Subjects were mothers of consecutive, live, singleton, full term neonates delivered at the Wesley Guild Hospital, Ilesa, Nigeria between January and August 2002. Each placenta was weighed and the placental to birth weight percent was calculated. The socio-economic classes of the parents, nutritional status of the mothers using the Body Mass Index (BMI), age and parity of the mothers, gestational ages of the babies derived from the mothers LMP and/ or Dubowitz score, as well as the weight and ponderal index of babies were all recorded. Foetal malnutrition/wasting was diagnosed using Clinical Assessment of Foetal Nutritional Status (CANS) and the score (CANSCORE) as adapted by Metcoff. The mean placental weights were examined in relation to maternal age, BMI, parity and socioeconomic class and the babies ponderal index, birth weight, length, occipitofrontal circumference and presence or absence of Foetal Malnutrition (FM). A total of 473 mothers and their babies were assessed. These babies consisted of 246 [52%] males and 227 [48%] females giving a male: female ratio of 1.08:1. The placental to birth weight percent (placental ratio) ranged between 17.8 and 18.7% with a mean of 18.4%. The mean placental weight for males was significantly higher than for females 577.44 (SD130.58)g versus 551.94 (SD108.62)g, t= 2.3, p< 0.025.The mean placental to birth weight percent for males and females were 18.2 and 18.5%, respectively. Younger aged mothers, low BMI (< 18.5kg m ²), low socioeconomic class (III-V) and lower parity (I and II) mothers had lower placental. Female sex, low birthweight babies, presence of foetal malnutrition (FM) and low ponderal index (< 2.32g cm ³) babies had significantly lower placental weight than otherwise (p< 0.05 at least). The estimates of regression coefficients distribution for the variables also show that high Placental to Birth Weight Percentage (PBWP) has significant independent effects on the presence of low birth weight at term, low ponderal index and presence of severe birth asphyxia. Placental weight and placental to birth weight percent are therefore useful in the identification of babies at risk of foetal malnutrition. Low placental weight and foetal malnutrition may have similar aetiopathogenesis. Further study of the placentas may therefore give information which may be useful in preventing these complications.