The number of people affected by serious youth violence fell by 30% with 1,900 fewer victims over the past financial year, according to the Met.
Overall, recorded crime in London fell by about 6% with 45,000 fewer reports between 2012-13.
The Met said personal thefts have gone up by 17% on the year before, with 70% involving mobile phones being taken.
Former Met officer Mike Pannett said he was concerned how the crime reduction would continue to improve.
He said: "Although I think it's great news, what I'm going to be looking towards is how that is going to be sustained; that level of reduction going forward over the next two to three years"
The Met said it had taken proactive measures which had led to there being a drop in crime.
It said the launch of the Trident Gang Crime Command to tackle an estimated 250 active criminal gangs in London, using a combination of enforcement and preventative approach, has had its impact.
Offences involving weapons also decreased with knife crime reducing by 20% and gun crime down by 20%.
Recently the unit lost its brief to investigate firearms deaths as the force said it had led to an "unhelpful" situation where murders were distinguished on the basis of the weapon used, when the same offenders could be involved in both knife and gun deaths.
Homicides have remained at a similar level with 106 deaths, compared to 103 last year - the lowest number in over 40 years.
Victim Support said it hoped the 16% rape increase was due to people feeling more confident about reporting it.
Jeff Gartner, from the charity, said: "I think there's been a real effort by the Met to look at the culture there is around the investigation of rape and I hope people are getting more confident and of course people need a good deal of support when they report a rape."
The Mayor of London Boris Johnson said: "London is one of the safest big cities in the world and it's great news that crime rates are continuing to fall.
"This is testament to the sterling work our cops are doing, and we are keeping bobbies on the beat to continue the fight against crime."