Featuring the UK's Engelbert Humperdinck and Ireland's Jedward, the 210-minute marathon commanded an average audience of 7.47m (36.2%) on BBC One between 8pm and 11.30pm.
While not able to match last year's 11-year high, Eurovision peaked with an impressive 9.6m at 11pm, despite the fact that Humperdinck was garnering only a small proportion of votes.
Some 2.01m (24.2%) stayed up for the 11.45pm repeat of documentary Bee Gees: In Our Own Time, which aired as a tribute to the late Robin Gibb.
However, The Voice UK plunged to a new low of 4.49m (28.8%) at 6.30pm, although the programme is currently 'Most Popular' on BBC iPlayer.
Over on ITV1, Roy Hodgson's first match as manager of England in a friendly against Norway attracted 4.64m (23.5%) between 7pm and 10pm, managing a peak of 6.6m at 9pm.
Channel 4's screening of The Lord of the Rings: The Two Towers appealed to 1.05m (5.6%) between 6.30pm and 10pm, adding a further 255k on +1.
The Chelsea Flower Show ended with 1.36m (7.5%), and was BBC Two's best-rated programme of the night, while Channel 5's CSI: NY took 1.15m (5.2%) at 10pm and 105k on +1.
Overall, BBC One beat ITV1 in primetime with 33% against 19.3% (+1: 0.3%). Channel 4 was far behind in third place with 5.2%, while BBC Two and Channel 5 followed with 4.3% and 3.9% (+1: 0.2%) respectively.
BARB ratings data supplied by Attentional