This thesis presents two data compression methods for digital electrocardiogram (EGG) signals. The first method is proposed for the compression of single lead EGG data. Various coding technicgies such as Sub-Band Transform and Variable Length Godings are used to realize that purpose. Data size reduction which is a problem in EGG databases is chosen as an application and successful results are achieved during simulations. The second algorithm is proposed for the multilead EGG data compression. A linear transform is applied to samples of the eight standard EGG lead signals. The resulting transform domain signals are compressed using various coding methods, including multi-rate signal processing and transform domain techniques. Higher compression ratios are achieved compared to the single channel compression techniques.