Better Together: Insero & CDLM

Insero & Company CPAs, P.C. and Ciaschi, Dietershagen, Little, Mickelson & Company, LLP will merge to form Insero & Co. CPAs as of January 1, 2016. Click here to read the full press release.

  • The same quality service team you already know
  • Over 125 team members in Ithaca, Cortland, Watkins Glen, Corning, and Rochester
  • Global reach, national strength, and local presence
  • Deep technical bench
  • Industry experience in government, not-for-profit, family businesses, employee benefit plans, and outsourced accounting

You Deserve The Highest Standard

The Highest Standard is not about being the largest or the most visible. It's not a vague promise or merely a tagline.

Insero has grown into one of the premier CPA firms in Western, Central, Upstate, and the Southern Tier of New York through uncompromising commitment to serving clients through hard work, tenacity, passion, and focus. The result is that our clients reach unparalleled heights of success - measured in more than just dollars.

Uncompromising commitment to deliver unparalleled heights. This is the highest standard.

Success is not born of a single event. Your relationship with your accounting firm shouldn't be either. On our site you'll see how the highest standard can benefit you. Whether through audit, tax, outsourced accounting, risk management, or business advisory services, you can count on us to listen to your situation, deliver solutions to your challenges, and bring you the ideas to take you and your business to the next level of success.

Please, explore our site and learn more about our promise to deliver The Highest Standard. 

Government/Not-for-Profit Agencies
Government and Not-for-Profit Agencies


Our Team

Nancy E. Catarisano, CPA
John H. Dietershagen, CPA
Michael J. Catallo, CPA
Kimberly W. Gangi, CPA
Louis J. Gangi, CPA
Michael L. Giess, CPA
Lesley L. Horner, CPA
Debbie C. Jordan, MBA, CPA
Patrick S. Jordan, CPA
Richard A. Krucher, CPA
Vincent A. Leo, CPA
Michael D. Marafioti, CPA
Jennifer R. Martlew, CPA, CFE
Timothy M. McLaughlin, CPA
Jerry E. Mickelson, CPA
Steven M. Mills, CPA
Duane R. Shoen, CPA
D. Leslie Spurgin, CPA
Thomas K. VanDerzee, JD, CPA

Frank A. Insero, CPA
Frederick J. Ciaschi, CPA

Manager Profiles


Rochester, New York Rochester
2 State Street, Suite 300, Rochester, NY 14614
Ph: (585) 454-6996 | Fax: (585) 454-4024

Ithaca, New York Ithaca
401 E. State Street, Suite 500, Ithaca, NY 14850
Ph: (607) 272-4444 | Fax: (607) 273-8372

Corning, New York Corning
5 E. Market Street, Suite 102, Corning, NY 14830
Ph: (607) 973-2075 | Fax: (585) 454-4024

Cortland, New York Cortland
39 Church Street, Cortland, NY 13045
Ph: (607) 753-7439 | Fax: (607) 753-7874

Watkins Glen, New York Watkins Glen
2 N. Franklin Street, Suite 330, Watkins Glen, NY 14891
Ph: (607) 535-4443 | Fax: (607) 535-6220

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 ©2015 Insero & Co. CPAs
Rochester| Ithaca | Corning | Cortland | Watkins Glen