Tens of thousands of people braved heavy rain and thunder Saturday night to see Paul McCartney perform a charity concert on Kiev’s central Independence Square.

The outdoor show, the first in Ukraine for the former Beatle, was billed as the biggest concert ever in the former Soviet republic. It was broadcast live on national television and on giant screens in five cities. Georgian President Mikheil Saakashvili was in attendance.

The square where Mr. McCartney played was the site of the Orange Revolution in 2004, when peaceful mass protests overturned a fraudulent election and brought a pro-Western opposition leader to power.

Organizers said the money raised will be spent on diagnostic equipment for Ukraine’s National Cancer Institute’s children’s department. Many children now seek treatment abroad because Ukraine lacks the necessary equipment.

The concert was free but the organizers were asking for donations from Ukrainian businessmen and others.

More than 500 people have contributed a total of about $600,000 and donations were continuing to come in, Tatiana Overina, a spokeswoman for the Victor Pinchuk Foundation, which organized the concert, said.

Mr. Pinchuk, a billionaire businessman and Ukraine’s richest man, established the foundation in 2006 to contribute to the modernization of Ukraine and bring forward a new generation of Ukrainian leaders.