Of the total assembly members with criminal background, 98 (40 per cent) have serious charges, including murder, attempt to murder, communal disharmony, kidnapping and crimes against women, says the study by the Bihar Election Watch and Association for Democratic Reforms (ADR).
Charges have been framed against 70 members with criminal background, it said.
"Out of the 142 MLAs who have declared pending criminal cases against them, 70 (49 percent) have declared that the charges for these cases have already been framed by the court of law," the study said.
Eleven MLAs have cases related to murder and attempt to murder. Of these, four MLAs are from the Rashtriya Janata Dal (RJD).
During the 2010 Bihar assembly elections, of 228 MLAs analysed, 76 (33 percent) had serious criminal cases against them, it said.