Unmanned stations like that where City lawyer Thomas ap Rhys Pryce alighted before he was stabbed to death, are to get a security boost, says the mayor.
Mr Rhys Pryce was stabbed shortly after leaving the station
Concern grew about stations left unmanned late in the evening, while services still run, after Mr Rhys Pryce died near Kensal Green, north London.
The franchise for Silverlink's suburban network is due to expire in 2007.
Ken Livingstone said the new franchise would specify that all stations had to have staff while they were open.
He said improving security at stations across the Silverlink network was part of the talks between Transport for London and the government about the handover of the Silverlink.
Mr Livingstone said: "I want to make this absolutely clear the franchise will specify that all stations have to have personnel while they are open.
"Nobody bidding will be considered unless part of their bid guarantees that all the existing Silverlink stations which are not staffed are staffed... from the beginning to the end of the day.
"We will not consider any bid for a franchise that does not include that complete commitment that staff will be at every station throughout its entire opening hours."
Mr Rhys Pryce was killed shortly after leaving Kensal Green station in north London on his way home from a night out on 12 January.
Shortly before he was stabbed, another man was robbed at the station.
Two teenagers have been charged with robbery and murder.