A Sainsbury's Local convenience store has opened in Great Maze Pond on the Guy's Hospital site.
Plans for the mini-supermarket have been in the works for more than two years.
Sainsbury's took over the outpatient pharmacy at Guy's Hospital in a controversial deal agreed in 2012.
Now the pharmacy has been combined with a small convenience store occupying the former New Salomons Centre building in Great Maze Pond.
The new Sainsbury's Local is open daily 7am-11pm.
For the latest local news and events direct to your inbox every Monday, you need our weekly email newsletter SE1 Direct.