Law Offices of Jeanmarie P. Costello

Serving your legal needs since 1986


Call us (631) 727-1090


Matrimonial & Family Law


Jeanmarie P. Costello is committed and compassionate in her representation of clients who are experiencing the devastating effects of a divorce or separation. Jeanmarie P. Costello argues strenuously on behalf of her clients, approaching each case with empathy and expertise in order to protect the client’s rights.
Jeanmarie has appeared in many matrimonial and family law matters in the Supreme and Family Courts throughout the State of New York. Jeanmarie is often consulted by members of
the New York Bar on an “of counsel” basis in matrimonial matters and has been a member of the Assigned Counsel Panel in Family Court. Jeanmarie has been a Law Guardian in both Family Court and Supreme Court from 1986-1995 and has lectured to women’s and community groups on matrimonial and family law and in Youth Courts in the Towns of Southampton and Riverhead, as well as for the Suffolk Academy of Law in the areas of custody, visitation and adoptions. Jeanmarie is a member of the New York State Bar Association Family Law Section and a member of the Suffolk County Bar Association Matrimonial Family Section and member of the Suffolk County Women’s Bar Association.
Matrimonial Matters

  • Contested and Uncontested Divorces
  • Custody, Visitation and Child Support
  • Spousal Support
  • Equitable Distribution of Marital Assets
  • Separation Agreements
  • Pre-Nuptial and Post Nuptial Agreements



Family Law Matters

  • Custody
  • Parenting Time (Visitation)
  • Paternity
  • Child Support
  • Spousal Support
  • Orders of Protection
  • Adoptions
  • Grandparent Visitation


*** The Law Office of Jeanmarie P. Costello also handles most Misdemeanor Criminal Offenses and Traffic Violations

Wills & Estates


Jeanmarie P. Costello is a member of the New York State Bar Association Section on Trusts & Estates. Jeanmarie P. Costello has handled numerous probate proceedings in Suffolk County Surrogate’s Court as well as prepared and executed Last Wills and Testament, Powers of Attorney, Health Care Proxies and Living Wills for her clients.
Jeanmarie is often called upon to perform the services of a guardian ad litem for those who are infants or incapacitated

Real Estate


Jeanmarie P. Costello has over 25 years of experience advising individuals and businesses in the process of selling or purchasing real estate. This includes reviewing and preparing purchase agreements, title searches, and all other necessary tasks to reduce the potential risks inherent in real estate transactions.
Jeanmarie has taught business law at Suffolk Community College and was an instructor at the American Real Estate School, preparing real estate sales persons / brokers for their licenses.
Jeanmarie’s extensive knowledge of the local East End Real Estate Community makes her a truly unique Real Estate Attorney. Jeanmarie’s attention to detail, accuracy and relationships distinguishes Jeanmarie P. Costello from her peers.