The series was adapted by Anthony Horowitz and Douglas Watkinson from Caroline Graham's Chief Inspector Barnaby novels, with Horowitz adapting the majority of the early episodes.

Neil Dudgeon, who now plays DCI John Barnaby, actually first appeared in the show back in series 4's episode 'Garden of Death', playing a tongue-in-cheek, sex-obsessed gardener named Daniel Bolt.

Before Neil Dudgeon took over the lead role, his character John Barnaby was introduced as a guest in the series 13 episode 'The Sword of Guillaume' ahead of John Nettles' retirement from the role of Tom Barnaby.

The pilot episode, 'The Killings at Badger's Drift', was the highest-rated single drama programme of 1997 in the UK, watched by 13.5 million viewers.

For the 100th episode, 'The Killings of Copenhagen', the crew filmed on location in central Copenhagen at sites like Rådhuspladsen, Nyhavn, and the Copenhagen Police Headquarters, making it one of only a few episodes to be set outside the fictional county of Midsomer.

The show's distinctive waltz theme is performed on a theremin, played by Celia Sheen; from series 14 onward the closing titles instead use a solo violin version, and one special episode even featured a jovial clarinet arrangement to mark the show's 25th anniversary.

In 2011, producer Brian True-May was suspended after telling Radio Times that the show had no non-white characters because it was 'the last bastion of Englishness', a controversy that led to his eventual resignation as producer, though the show subsequently increased on-screen diversity, including adding Asian actress Manjinder Virk as pathologist Kam Karimore from series 18.

A 25th anniversary documentary, 'Midsomer Murders – 25 Years of Mayhem', revealed pre-fame guest appearances by actors Orlando Bloom and Henry Cavill on the show.