The number of prisoners who died in custody jumped by nearly a quarter in the year to March to reach its highest level for almost a decade, official figures show.
A total of 225 inmates died in jail in 2013/14, compared to 181 in the same period the previous year.
This was the highest number since 2005.
Meanwhile the number of attacks on prison staff soared to its highest level for six years, prompting suggestions that jails in England and Wales have become "places of extreme violence".
The death rate increased to 2.7 deaths per 1,000 prisoners from 2.1, the Ministry of Justice (MoJ) statistics show.
Of the fatalities 88 were self-inflicted, 127 were from natural causes, three were homicides and the remaining seven were listed as "other".
It was the highest number of prisoners taking their own deaths since 2005.
The number of incidents in which inmates self-harmed increased by more than 750 from 22,722 in 2012/13 to 23,478 in the 12 months to March.
The figures also showed that the number of attacks against staff has increased by more than a tenth to 3,363 in the 12 months to March - the highest number since 2007.
Of those incidents, 370 were classed as "serious" assaults - the highest since 2005.
A total of 15,033 assaults, including fights, were recorded in prisons - an increase of nearly 1,000 compared to the previous year.
The MoJ said in the report that the surge was "slightly overstated" because of improvements in reporting of assault incidents.
Frances Crook, chief executive of the Howard League for Penal Reform, said: "Prisons are becoming places of extreme violence as men are caged with nothing to do all day, and in some terrible cases they have become death traps.
"The contrast with the probation service is stark, as the final year of more than a century of success at keeping the public safe is finally destroyed.
"The world has truly gone mad when prisons are getting more violent but have government support, and probation that reduces crime is being destroyed."
Justice Minister Andrew Selous said: "Reducing the number of self-inflicted deaths in custody is a key priority and we are working hard to understand the reasons for the recent increase.
"But this is a complex issue and there is no simple explanation, with the prison population containing a high proportion of very vulnerable individuals.
"All prisons have procedures to identify, manage and support people who are at risk of harm to themselves, and additional resources and support are being provided to improve this safer custody work.
"All deaths are subject to investigation by the police and the Prisons and Probation Ombudsman and a Coroner's inquest, and strenuous efforts are made to learn lessons from these processes.
"An independent review into self-inflicted deaths amongst 18-24 year olds is also being conducted to help identify learning points that can be applied across all age groups."