Buffalo police commissioner Daniel Derenda says officers arrested George Torres, 51, of 55 Garner Avenue.
He's charged with possessing with intent to distribute more than 200 grams of heroin.
"Mr. Torres ... [has] been a long time believed heroin dealer on the west side, a source for many, many years. The six-month long investigation into him has led to his arrest," Buffalo police commissioner Daniel Derenda said in announcing details during an afternoon news conference.
In searching Torres' home on Tuesday, officers also seized three handguns and $368,000 in cash. Torres is being held without bail, pending a detention hearing next Tuesday morning.
Torres made an initial appearance before U.S. Magistrate Hugh B. Scott on Thursday morning.
The criminal complaint is the culmination of an investigation by members of the Buffalo Police Department, special agents of the Federal Bureau of Investigation under the direction of Special Agent in Charge Christopher Piehota, and the Bureau of Alcohol, Tobacco, Firearms, and Explosives, under the direction of Resident Agent in Charge Frank Christiano, according to the office of U.S. Attorney William Hochul, Jr.
Assistant U.S. Attorney Timothy Lynch is handling the case, according to Hochul's office.