Various biological objects have been studied by means of the proton radiography using laser-generated plasma as a source of ions. It is established that the best quality of imaging can be achieved using double laser targets comprising a hydrocarbon plastic film covered with a thin layer of heavy metal. The laminar character of the ion flux produced by such sources makes possible the imaging of objects with dimensions (∼2 μm) smaller than the ion beam spot size. The minimum size of an object that can be resolved by laser plasma ion-ography with proton beams is estimated.