A portable baby bottle blender includes a baby bottle having a top collar with external threads and a bottom collar with external threads. A top cap has a central aperture. The top cap is internally threaded to be removable threaded onto the top collar of the baby bottle and holds a feeding nipple extending through the central aperture of the top cap onto the top collar. A sealing O-ring fits onto the bottom collar of the baby bottle. A bottom cap has a rim internally threaded. An agitating unit is centrally retained within the bottom cap. When the rim of the bottom cap is removably threaded onto the bottom collar of the baby bottle and against the sealing O-ring, the agitating unit extends into the bottom collar of the baby bottle. A base member has a top recess to receive the bottom cap on the baby bottle therein. A spur-crown gear coupling is for operating the agitating unit, so that the mixing blade assembly mixes formula within water placed through the top collar of the baby bottle.