Hammerjacks Concert Hall and Nightclub was a large concert hall in downtown Baltimore through the 1980s and into the 1990s owned by Louis J. Principio III The club attracted many big-name national acts, but also showcased many rising stars in the music world. The bands ranged from punk, glam, and heavy metal acts most commonly associated with the venue (e.g., Guns n Roses, Kix, Ratt, Skid Row or Extreme) to pop (e.g., Badfinger) and alternative rock groups (e.g., Goo Goo Dolls). The club was often frequented by hard core patrons and musicians donning big hair, leather, lace, spandex, and heavy makeup, and was considered a "hard rock shrine." Hamerjacks, however, attracted audiences with other attire as well. It was torn down on June 12, 1997 to make way for M&T Bank Stadium parking lot. Hammerjacks was billed as "The largest nightclub on the east coast."
A third version of Hammerjacks opened in a different location, which had formerly been used as a car wash, in Baltimore. It was then put under new management in 2004, but has now been closed.
The club was featured in the John Waters' 1994 film Serial Mom, with grunge band L7 playing the band Camel Lips. It was the location where Kathleen Turner's character Beverly Sutphin was arrested for murder. Interior and exterior views of the club have been featured in music videos, including the band Kix. An image of a sign for the club appeared on the Iron Maiden album "Somewhere In Time".
As of July 2, 2011, the Trademark Electronic Search System (TESS) listed five different records pertaining to the trademark "Hammerjacks." The only active application for the trademark was by Hammerhouse Designs LLC. The attorney of record was Lawrence E. Laubscher, Jr. The resident agent was listed as Kevin Butler. The application for this trademark was filed January 27, 2011 and published for opposition April 19, 2011. The other records pertain to abandoned applications and registrations. Official merchandise can still be purchased on the Hammerjacks' website, which is operated by Hammerhouse Designs. In 2010 Kevin Butler acquired the lapsed trademark. Kevin Butler has made extensive plans and investment to open a new 57,000 sq. foot nightclub nearby the old location.