As adverse effects and health implications of human exposures to petroleum products (crude oil) remains an issue of public concern, interests on the different adverse effects on various body system has grown in recent years. Current study investigated the duration and age dependent effect of exposure of the cardiovascular system (CVS) to gas flaring and crude oil contamination in selected communities of Delta State, southern Nigeria. Two Hundred and Forty (240) subjects, who were exposed to gas flaring and crude oil contamination were ethically recruited from Agbarho [Ughelli North Local government Area (LGA)] and Bomadi (Bomadi LGA) in Delta State, Nigeria. One hundred and twenty (120) non-exposed individuals were also recruited (control) from Abraka, a non-gas flaring community in Ethiope East LGA of the same state. Thereafter, subjects were matched by gender, age, and duration of stay (exposure) to gas flaring and oil contamination in selected towns. In any case, cardiovascular parameters [systolic blood pressure (SBP), diastolic blood pressure (DBP)] were measured, while obtaining their pulse and mean arterial pressures (PP and MAP respectively) from measured variables. After statistical analysis (using the student t-test), study observed (at p < .05) a statistically significant increase in SBP and MAP for subjects above 10 years and 6 – 10 years of gas flaring exposure (Experimental groups) compared to those who had been exposed for just 1 – 5 years (Control). Study also observed a statistically significant increase in SBP and DBP (of females) for crude contamination exposed subjects for ages greater than 5 years compared to control. A duration-dependent exposure of subjects to increased SBP and DBP, following exposure to gas flaring and crude oil contamination was thus established. Apparently, exposed males showed an increase in average values of PP, MAP, SBP and DBP than the female counterparts. Study therefore ascertained findings from previous studies relating to cardiovascular changes on gas flaring and crude oil exposed humans; confirming gas flaring and oil contamination as potent elicitors of hypertension. Thus, environmental pollutants may act as markers for the screening and identification of CVS high-risk population, prior to actual diagnosis, intervention and prognosis of hypertension. We recommend periodic epidemiological assessment of environmental pollutants as a factor for indexing municipal risk of hypertensive individuals.