This paper investigates determinants of financial saving in Tanzania during the period 1967- 2010. Both OLS method and dynamic error correction (coitegration) model (ECM) approaches were employed to test the hypothesis that the interest rate elasticity of financial savings was positive during the study period. The regression results rejected the hypothesis that the interest rate of financial savings was negative and statistically insignificant for the period 1967-1986, a period that was characterised by staunch Government regulation and control of the financial sector. Also unexpectedly, the results rejected the hypothesis that the interest rate elasticity of financial savings was positive during the period 1987-2010, a period that was characterized by market determined interest rates. The results also showed a decrease in absolute size of the real interest rare elasticity of financial savings over the two sub-sample period. Several robustness tests confirmed the estimated sign and sensitivity of financial savings to real interest rates for both sub-sample periods. The results, however, are inconsistent with the traditional theory and therefore demands for further empirical investigation.