This paper provides evidence on the negative impact of the assessment of capital flight on economic growth of Nigeria for 40 years (1970-2009). It provides a comprehensive analysis of capital flight and its resultant impact on domestic investment and the growth rate of the economy. The study used cointegration and Error Correction Mechanism (ECM) as its main estimation techniques. It was discovered that capital flight and its assessments are significant factors for explaining economic trends in Nigeria. It was also discovered that capital flight have negative impact on the economy. Consequently, it is recommended that funds from foreign sources in form of loans, gifts, grants and aids should be judiciously used for economic development of Nigeria. Above all, government should provide enabling environment for business to thrive thereby encouraging foreign direct investment and discouraging capital flight.