The actresses have notched up almost 100 years of combined service on the 'Street', playing characters that have endeared themselves to millions of viewers since they first joined the cast in the 1960s.
Knox, 77, is best known to viewers as flame-haired stalwart of The Kabin, Rita Sullivan, while co-star Derbyshire, 79, has played one of TV's most enduring figures, having first appeared as Emily Bishop nearly half a century ago.
Speaking after the Buckingham Palace investiture ceremony, Knox said: "It's very overwhelming quite honestly because it's something I've done all my life and loved and suddenly I've got an honour.
"I suppose we do give a service, so many millions love the programme, so there you are - it's still very surprising."
Asked whether the Queen is a fan of the soap, the veteran actress replied: "I'm rather led to believe she does watch when she has time and she has visited the Street so she does know about it."
Both actresses praised fellow cast members and the work of those behind the scenes from the director and writers to make-up artists for making the long-running series a success.
Knox said: "They are a great team of actors and they are portraying marvellous people with great humour.
"Australia, New Zealand, Canada, all these places adore the Street so we must be doing something right."
We have marvellous storylines, very strong ones, and we have hit a nerve with the nation for almost 50 years and that's pretty special for a programme to do that.
Barbara Knox
Knox's character has had her ups and downs over the years since first appearing on the cobbles in December 1964 as Rita Littlewood, when Stan Ogden bought her a drink in the Rovers Return.
In 2006, Knox scooped the British Soap Award, along with Malcolm Hebden who plays Norris Cole, for best on-screen partnership.
The two actors have honed something of a comedy double act, with Rita often giving deadpan put-downs to Norris's fanciful ideas.
Asked what Norris would say about her award, she replied: "Something disparaging."
Derbyshire said her decision to take on the role of Emily, which was only supposed to last a week, was the best career move of her life.
Her character is now the second longest-running figure in the soap, after Ken Barlow, played by Bill Roache.
The actress said: "I went for an audition for the show after it had started and they said 'It's all cast but we think it will probably run a bit more than 13 weeks' - what an understatement.
"They said 'The part's only for one week', but I thought 'It's work' and took it - probably the most amazing decision I ever made."
Derbyshire made her first appearance in the Street in January 1961 - a month after the show was first aired on December 9 1960 - when Emily clashed with Ena Sharples (Violet Carson), the caretaker of the Glad Tidings Mission, over clearing up after services.
The character may enjoy a quieter life now, but in the 1960s Emily jilted Leonard Swindley (Arthur Lowe) on their wedding day and later enjoyed a passionate fling with Miklos Zadic (Paul Stassino).
She described how her father summed up her unusual life as a soap actor: "It's like living a double life. My father once said to me 'Doesn't it strike you as strange, pretending to be somebody else?'."
Actress Anne Reid, who also starred in Coronation Street, was awarded an MBE during the ceremony.
The 75-year-old played Ken Barlow's doomed first wife Valerie before she left the long-running soap in the early 1970s and forged a career which has seen her became a versatile performer, playing both comic roles and serious parts in costume dramas and films.
The actress described the honour as a shock and said it was her ability to play characters and do comedy that kept her in work.
She said: "I think we're very lucky in this business because we don't have to retire - as long as you can remember the lines and keep going it's a good life."