The first cockroaches Thomas F. Cooney saw skittering across the floor of his $470-a-month high-rise apartment in Arlington did not seem that worrisome.

"I grew up in the city of Boston and I've lived abroad so I'm not overly sensitive about them," said Cooney, a 27-year-old attorney.

But Cooney said he knew he had to move when he was awakened from a sound sleep early one morning to find a roach scurrying across his forehead.

Yesterday an Arlington judge sided with Cooney, saying that no one should have to share an apartment with scores of uninvited six-legged guests.

"This is a simple case as to whether (Cooney) received a clean apartment," said General District Judge Thomas R. Monroe. He ordered the Charles E. Smith Co., manager of the 912-unit Crystal Towers complex, to pay Cooney $900 damages.

Smith Co. attorney Nelson Deckelbaum said he probably would appeal the decision, which he called "patently in error."

Cooney had filed a $2,500 lawsuit against the firm seeking to recover back rent, moving and fumigation expenses, plus "a minor amount for mental anguish." He testified during a two-hour trial yesterday that neither cleanliness on his part nor repeated visits by the building exterminator made any difference.

"I have a glass-top dining room table," said Cooney. "The small roaches would climb up the wooden pedestal and crawl on the underside."

Some nights Cooney said he would sleep with the lights on believing that it would scare the bugs. Another night he camped out on a leather couch in the elegant lobby of the building after finding two roaches crawling up his leg.

"I saw roaches crawling in the stairwell, in the common areas and underneath the door to my apartment," said Cooney. Once he captured 15 roaches, put them in a jar and presented it to the apartment's manager as evidence of the problem, he said.

In desperation, Cooney said he stayed at friends' homes, ate his meals out. He paid an exterminating firm to look at the problem. "They told me I had two kinds of roaches and it would take three to six months to get rid of them with no guarantees."

Smith officials countersued for $480 in back rent and expenses but their pleas were denied. The firm agreed that Cooney had a problem.

Carol Ann Watson, a former resident manager at Crystal Towers, testified that twice when she accompained an exterminator to Cooney's apartment she found "crumbs on the countertop, trash in paper bags in the kitchen and clothes strewn throughout two bedrooms."

Watson also testified that after one exterminator's visit she counted 15 dead roaches in his apartment. Two weeks later on a follow-up visit Watson said she found the same roaches lying in the same places.

"We all have to live with roaches," said Deckelbaum. "Last night in my apartment which is kept fastidiously clean by my wife we found roaches in the microwave oven."

"Charles E. Smith is a responsible landlord," said Decklebaum. "A landlord is not an insurer that a man's apartment is not going to have roaches."

"We could speculate as to why he moved," said Deckelbaum, citing Cooney's testimony that he now lives with a woman -- and no roaches -- in a townhouse in Alexandria.

But Monroe said the Cooney's present living arrangements were irrelevant. The abundance of roaches, the judge said, interferred with Cooney's "quiet enjoyment" of his two bedroom apartment and essentially made it uninhabitable.

Arlington officials said yesterday that they have received few complaints about roaches by residents of the Smith apartments, one of the largest apartment complexes in the area.

"There's probably not one apartment building in Arlington or anywhere else that doesn't insepctions supervisor Ted Payne. Scientists say that roaches are indomitable creatures that have been around for 300 million years and probably would survive a nuclear holocaust.