Rescue workers were still searching for survivors and bodies on Thursday morning in neighbourhoods including Tallet El Khayat, where apartment blocks and shops were reduced to rubble.
The bombardment came only hours after a ceasefire was announced in the US-Iran conflict, shattering hopes in Beirut that the wider region might be moving towards calm.
Israel said the truce did not apply to its war with Hezbollah and described the operation as its largest coordinated strike of the current conflict, saying more than 100 targets were hit within 10 minutes across Beirut, southern Lebanon and the Bekaa Valley.
Residents said there had been no warning before the attacks, which sent people running into the streets as smoke rose above the capital.
The death toll made Wednesday the deadliest day in the latest Israel-Hezbollah war, underlining how quickly a diplomatic breakthrough elsewhere can fail to protect civilians in Lebanon.