The effect of supplementing a regular diet with ascorbic acid on haematological indices was studied in teenage pregnant women attending antenatal clinics of three government hospitals in Ibadan, Nigeria. Informed consent was obtained from 45 subjects and this formed the sample for the study. The subjects were divided into two groups: experimental group consisting of 30 subjects and control which consisted of 15 subjects. Baseline records of four blood parameters were obtained from all the subjects before each member of the experimental group was given a daily dose of 100mg ascorbic acid supplement for four weeks. The initial records of the haemoglobin levels, haematocrit value, red blood cell count and Plasma Ascorbic concentration of the experimental subjects ranged between 6.4 to 19.6gl 100ml, 24% to 37%, 1.62 x 106 to 3.87 x 106/mm3 and 0.00mg/100ml to 1.47mg/100ml respectively. In the control subjects, these range between 10.0 to 19.2g/100ml, 25 to 38%, 2.63 x 106 to 4.37 x 106/mm3 and 0.05 to 1.46mg/100ml respectively also. The experimental group that was given a daily ascorbate load of 100mg above their normal dietary intake for four weeks period recorded a general increase in the blood parameters. The haemoglobin level, haematocrit, red blood cell count and plasma ascorbate levels rose from 7.1 to 20.0g/100ml, 30 to 39%, 2.14 to 4.22 x 106/mm3 and 0.20 to 2.06 mg/100ml respectively. The low levels were still recorded in the control group after 4 weeks study period and this ranged between 10.3 to 18.2g/100ml, 25 to 37%, 2.94 x 106 to 3.64x106/mm3 and 0.00mg/100 to 1.45mg/100ml in that order as well. The 4.8 x 106/mm3 which is the normal standard value of red blood cell and 40 - 47%, which is that of the haematocrit, were not met by all the subjects at the initial record. After 4 weeks of the supplementation (in the experimental subjects), these two values were still not met though there were some appreciable improvements. Generally, the data obtained from the study showed that ascorbate supplementation produced a positive haematological response in teenage pregnant women.