Preparation of amorphous solid dispersions (ASD) containing the active pharmaceutic ingredients (API) Lamivudine and Tenofovir Disoproxyl Fumarate by hot melt extrusion was investigated. These two drugs are currently used as drugs in first line treatment of patients with Acquired Immunodeficiency Syndrome (AIDS). Rheological studies of binary combinations of poly(vinylpyrrolidone-vinyl acetate) (Kollidon) and each API were performed at concentrations of 5, 15, 30 and 50 wt% to evaluate the compatibility of the system. In order to predetermine parameters for extrusion and the maximum concentration of API to be used without any precipitation, binary blends were first processed in the mixing chamber at 130°C using 10, 20 and 30 rpm. The samples were characterized by X-ray diffraction (XRD), infrared spectroscopy using attenuated reflectance (ATR FTIR), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The API were then extruded individually with Kollidon VA64 in a single screw extruder. Since it is a continuous process, the temperature profile and the screw rotation defined the final characteristic of the extrudate. The blends obtained were characterized by XRD, SEM, FTIR-ATR, DSC, thermogravimetry analysis (TGA). The results showed that it was possible to form combinations of binary ASD of Kollidon VA64/API in all cases. Extrusions in a twin screw extruder of Kollidon containing the two API were also carried out. Samples were characterized the by the above mentioned methods confirming the formation of ASD.