WASHINGTON — Democrat Robert Menendez holds a slight edge over Republican challenger Tom Kean Jr. in New Jersey’s Senate race in one poll and a larger lead in another survey, results released yesterday showed.

In the Quinnipiac University poll, Mr. Menendez holds a 49–44% advantage among 887 likely voters questioned from October 23–29. The margin of error was plus or minus 3.5%.

In a CNN poll, conducted from October 26–29 by Opinion Research Corp., Mr. Menendez had a 51–44% lead among 577 likely voters surveyed. The error margin was plus or minus 4%. Among 917 registered voters, Mr. Menendez was preferred 50–38%. This survey had a plus or minus error margin of 3%.

Mr. Menendez has held slight leads over Mr. Kean in recent weeks, and although poll results look good for Mr. Menendez, Quinnipiac University Polling Institute Director Maurice Carroll said the senator shouldn’t assume the race was won.

“New Jersey is a state where the numbers swing like a yo-yo, and it always makes up its mind late,” Mr. Carroll said.

The state’s large bloc of independent voters and suburbanites usually hold the key to victory. Mr. Menendez leads Mr. Kean among these voters, but not overwhelmingly, Mr. Carroll said.

Independents back Mr. Menendez 47–43% and women 57–34%. Men prefer Mr. Kean 54–40%, according to the Quinnipiac poll. Those surveyed said 74–14% that the campaign has been very dirty, Mr. Carroll said.

Mr. Kean has depicted Mr. Menendez as a corrupt politician although the Democrat has never been charged with any wrongdoing. Mr. Menendez’s tactic has been to link Mr. Kean to President Bush and his unpopular policies.