The singer leads the list - which was compiled by The Sunday Times - with an estimated wealth of £20 million.
This is in comparison with her 2011 fortune of £6 million, before her second studio album 21 sold over 20 million copies worldwide later in the year.
Cheryl Cole is in joint-second place with Leona Lewis and Katie Melua, who have all accumulated a bank balance of £12 million.
Joss Stone is fifth with £10m, which is up £1m from 2011. Charlotte Church, Craig David and Paolo Nutini are in joint-sixth position with £8m.
Newcomers to this year's list include all four members of JLS and Jessie J, who place at joint-14th with estimated fortunes of £5m each.
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The Sunday Times Rich List 2012 for young musicians aged 30 and under is as follows:
1. Adele (£20m)
2. Cheryl Cole (£12m)
2. Leona Lewis (£12m)
2. Katie Melua (£12m)
5. Joss Stone (£10m)
6. Charlotte Church (£8m)
6. Craig David (£8m)
6. Paolo Nutini (£8m)
9. Florence Welch (£7m)
10. Lily Allen (£6m)
10. Natasha Bedingfield (£6m)
10. Duffy (£6m)
10. James Morrison (£6m)
14. Nadine Coyle (£5m)
14. Taio Cruz (£5m)
14. Jonathan 'JB' Gill (JLS) (£5m)
14. Sarah Harding (£5m)
14. Marvin Humes (JLS) (£5m)
14. Jessie J (£5m)
14. Aston Merrygold (JLS) (£5m)
14. Nicola Roberts (£5m)
14. Kimberley Walsh (£5m)
14. Oritsé Williams (JLS) (£5m)
Watch the music video for Adele's 'Rolling In The Deep' below: