Ukraine
- Dnepropetrovsk maniacs (Viktor Sayenko, Alexander Hanzha and Igor Suprunyuck) - three 19-year-olds who murdered 21 people during a one-month period in 2007
- Anatoly Onoprienko – aka "The Terminator"; murdered 59 people from 1989 until his capture in 1996
- Serhiy Tkach – convicted of raping and murdering 36 women, but claims the total is 100
- Nighttime Killers (Vladislav Volkovich and Vladimir Kondratenko) – charged with shooting, stabbing and bludgeoning 16 victims to death in Kiev between 1991 and 1997; Kondratenko committed suicide in prison during the trial; Volkovich was found guilty and sentenced to life imprisonment
United Kingdom
- Beverley Allitt – aka "Angel of Death"; paediatric nurse who killed four babies in her care and injured at least nine others; sentenced to life imprisonment in 1991
- Robert Black – Scottish schoolgirl killer; convicted of three murders, suspected of many more
- Ian Brady and Myra Hindley – aka "Moors Murderers"; murdered five children, aged between 10 and 17 and buried them in Saddleworth Moor
- Leslie Bailey – killed at least three young boys in and around London in the 1980s
- William Burke and William Hare – notorious body snatchers in Edinburgh in the 19th century
- George Chapman – poisoned three women; suspected by some authors of being Jack the Ripper
- John Childs – murdered six people between 1974 and 1978; sentenced to life imprisonment
- John Christie – killed seven women (including his wife) and disputably one infant between 1943 and 1953 and hid them in his house and garden at 10 Rillington Place
- Mary Ann Cotton – British Victorian killer; said to have poisoned more than 20 victims
- Thomas Neill Cream – aka "Lambeth Poisoner"; began his killing spree in the United States then moved to London; hanged in 1892
- Amelia Dyer – murdered infants in her care; executed in 1896
- Kenneth Erskine – aka "Stockwell Strangler"; sentenced to life imprisonment in 1988 for murdering seven pensioners
- Steven Grieveson – aka "The Sunderland Strangler"; murdered three teenage boys in Sunderland, Tyne and Wear in 1993 and 1994
- John George Haigh – aka the "Acid Bath Murderer" and the "Vampire of London"; active in England during the 1940s; convicted of six murders, but claimed to have killed 9; executed in 1949
- Anthony Hardy – aka the "Camden Ripper"; convicted of three murders; suspected of at least four
- Trevor Hardy – aka "The Beast in the Night"; killed three teenage girls in Manchester from 1974 to 1976
- Colin Ireland – aka "Gay Slayer"; killed five gay men in the early 1990s
- Michael Lupo – aka "Wolf Man"; convicted of four murders and two attempted murders
- Bruce George Peter Lee – serial arsonist and killer
- Patrick Mackay – charged with the murders of five individuals, convicted of three; confessed to killing 11 people
- Peter Manuel – Scottish murderer of seven, suspected of killing 15; executed in 1958
- Robert Maudsley – killer of four; killed three in prison
- Peter Moore – businessman who killed four men at random in Wales
- Donald Neilson – aka "Black Panther; killed four people, including heiress Lesley Whittle
- Dennis Nilsen – killer of 15 (possibly 16) men between 1978 and 1983
- Colin Norris – nurse convicted of killing four patients in Leeds hospitals
- William Palmer – aka "Palmer the Poisoner"; doctor suspected of numerous murders, convicted of one; hanged on June 14, 1856
- Mark Rowntree – 19 year old who killed four people at random
- Amelia Sach and Annie Walters – murdered an unknown number of babies put up for adoption
- Harold Shipman – doctor convicted of 15 murders; a later inquiry stated he had killed at least 215 and possibly up to 457 people over a 25-year period
- George Joseph Smith – aka "The Brides in the Bath"; killer of three women
- John Straffen – child killer and Britain's longest serving prisoner until his death on November 19, 2007