Surveying more than 3,000 members of the general public, the poll showed only 49% of people aged between 16 and 34 years would recycle all they can, indicating a drop of 8% year-on-year.
The results additionally revealed that 70% of 35-54 year olds, 83% 55-74 year olds and 81% aged more than 75 are willing to recycle.
When analysed across all age groups, a decrease of 3% was observed compared to last year, as only 68% of residents said that they recycle all they can.
Serco Environmental Services business executive Robin Davies said: “It’s clear that the industry needs to do more to get millennials engaged in the benefits of recycling.
“With so much competition for young people’s time and attention, we need to find new and compelling ways to explain why recycling is so important, making it fresh and relevant for the social media generation.”
According to the poll, the most common reasons given by the millennials for not recycling were confusion, need for more frequent recycling collections and no availability of bins or bags.
The levels of recycling also varied by geographical location with Scotland residents being the most likely to recycle all they can (80%), followed by Wales (75%).
People living in London were found to be the least likely (54%) to recycle.
Future Thinking associate director Claire Tyrell-Williams said: “The results of this poll go against the received wisdom that young people are more interested in green issues than older generations.
“The challenge for the industry is to overcome the key barriers that prevent people from changing their behaviour and adopting recycling habits.”