The new store is located in the food hall at West Middlesex Hospital giving people access to a menu of freshly prepared Subs, wraps and salads.
Subway currently has 15 stores at hospital locations throughout the UK and Ireland.
Colin Hughes, country director for Subway UK and Ireland, said: "We are delighted to see ISS open its second Subway store in the UK, strengthening our partnership further. ISS shares the Subway passion for serving quality, delicious food, along with a key focus on providing excellent customer service.
“The new store at West Middlesex Hospital allows us to widen our brand reach in hospital locations, and provides patients, visitors and staff with nutritious meal options throughout the day.”
The new store is the second to be opened by ISS in the UK, following the first subway store at University Hospital Coventry.
Glynn Ford, franchise and brand manager of ISS, added: ”Subway is an ideal partner for our healthcare business, as we know our staff and visitors are looking for a fresh and healthy option during all parts of the day. With Subway’s innovative menu, we can always meet our customers’ expectations.
“The West Middlesex Hospital store will be the first Fresh Forward Subway store for ISS in the world - we have great excitement within our business and look forward to opening more stores globally.”