A high-efficiency regime of acceleration in laser plasmas has been discovered recently, allowing table top equipment to deliver doses of interest for radiotherapy with electron bunches of suitable kinetic energy. A R&D program aimed to the realization of an innovative class of accelerators for medical uses, through radiobiological validation, is in progress at CNR, Pisa. Actually, biological effects of electron bunches from laser-driven electron accelerator are largely unknown. In radiobiology and radiotherapy, it is known that the early spatial distribution of energy deposition following ionizing radiation interactions with DNA molecule is crucial for the prediction of damages at cellular or tissue levels and during the clinical responses to this irradiation. The purpose of the present study is to evaluate the radio-biological effects obtained with electron bunches from a laser-driven electron accelerator compared with bunches coming from medical radio-frequency–based linac's. To this purpose a multidisciplinary team including radiotherapists, biologists, medical physicists, laser and plasma physicists is working at CNR Campus and University of Pisa. Dose on samples is delivered alternatively by the “laser-linac” operating at the ILIL lab of Istituto Nazionale di Ottica and an RF-linac operating at Pisa S. Chiara Hospital. Experimental data are analyzed on the basis of suitable radiobiological models as well as with numerical simulation based on Monte Carlo codes. Possible collective effects are also considered in the case of ultrashort, ultradense bunches of ionizing radiation produced with the laser technique. This lecture will describe and shortly discuss most of the points above.