Yushchenko originally gave the assembly two days to approve the legislative package but twice had to issue decrees to extend the deadline by a single day.
Three key measures were adopted in the final stage of debate, all by overwhelming majorities, though the outcome remained in doubt until near the end.
Early in the evening deputies approved an electoral law setting down rules for the poll. These included a minimum 50 per cent turnout and restrictions on voting abroad.
The chamber went into a long recess until parliamentary leaders received news that the president had signed the law.
“At least one of the parliamentary faction leaders saw the law signed by the president,” Adam Martynyuk, communist deputy speaker, told the assembly.
“The president has therefore fulfilled his obligation and we have the grounds to carry on with our work.”
Members then gave final approval to revisions to the 2007 budget to finance the election and approved a new line-up for the central election commission.
The date for the election was set under a deal the president struck last weekend with Yanukovich, whose power base is in Russian-speaking eastern Ukraine. The two men held another in a long series of talks early on Friday before Yushchenko granted the latest one-day extension by decree.
The president had threatened on Thursday to call the election earlier – within 60 days – if parliament failed to pass all the required measures by the end of the day.