Natural cellulosic fibres from various varieties of banana plants such as Red Banana, Nendran, Rasthaly, Morris and Poovan have been extracted manually and the physico-chemical properties of these fibres are investigated. The tensile strength of these fibres varies from 176 MPa to 525 MPa. The untreated fibres have more tensile strength than the treated one. The thermal properties of these fibres are studied by Differential Scanning Calorimetry (DSC). Two DSC thermal peaks, one is around $25^{circ}C$ to $180^{circ}C$ and the other is around $155^{circ}C$ to $240^{circ}C$, are noticed. The tensile strengths have a direct correlation with the area of the lower thermal peak (enthalpy) and activation energy of the DSC, and also with the moisture absorption characteristics. The FTIR shows characteristic bands corresponds to cellulose. The reflections of the X-ray fibre diffraction pattern recorded for the banana fibre have been correlated with the mechanical strength.