Compression is an important part in image processing in order to save memory space and reduce the bandwidth while transmitting. The main purpose of this paper is to analyse the performance of 3-D wavelet encoders using 3-D medical images. Four wavelet transforms, namely, Daubechies 4,Daubechies 6,Cohen-Daubechies-Feauveau 9/7 and Cohen Daubechies-Feauveau5/3 are used in the first stage with encoders such as 3-D SPIHT,3-D SPECK and 3-D BISK used in the second stage for the compression. Experiments are performed using medical test image such as magnetic resonance images (MRI) and X-ray angiograms (XA). The XA and MR image slices are grouped into 4, 8 and 16 slices and the wavelet transforms and encoding schemes are applied to identify the best wavelet encoder combination. The performances of the proposed scheme are evaluated in terms of peak signal to noise ratio and bit rate.