The 61-year-old Maziarz has represented Western New York in the State Senate since 1995.
Maziarz becomes the fourth Senate Republican to announce they are leaving the Legislature.
Maziarz made his announcement late Sunday night, saying he wasn't as enthusiastic about mounting a campaign as he had been in the past.
Three other Republican senators have announced this year they won't seek re-election in the fall. Sen. Greg Ball honored a term limits pledge. Sen. Lee Zeldin is running for Congress and Charles Fuschillo left the Senate to become executive director of the Alzheimer's Foundation of America.
Senate Republican Leader Dean Skelos praised Maziarz' service on Monday and said Republicans expect to hold onto his seat in the fall elections.
Republican Gia Arnold and Democrat Johnny Destino had previously said they were running for the seat, but this announcement is expected to attract more people to the race.
Here is the text of the statement:
“It is no secret to my family and close friends that I have been considering retirement from the State Legislature for the last five years. And as I geared up for another long campaign season, I realized I just did not have the passion and commitment that I have had in the past to see it through.
“People will ask me why now and the simple answer is there is never the perfect time to step away. I had the honor of following the late John Daly into the State Senate. I remember him telling me when he left the Senate it was simply time for the next generation of leaders in the Legislature. After nearly two decades in office, I fully understand what he meant and feel that way today.
“My second daughter gets married this summer and that is a much bigger priority for me than another grueling campaign. My family has sacrificed enough for my public service through the years and I cannot ask for any more.
“To the people of Niagara, Orleans and Monroe counties who I have had the pleasure to represent since 1995, I extend my heart felt appreciation for your continued support. I always told people that being your Senator was the greatest job in the world, one I dedicated myself to 24 hours a day, seven days a week. We accomplished great things and I did my best to help my constituents with any problem…big or small. Thank you for giving a kid from North Tonawanda the chance to fulfill his dream of serving in the State Senate.”