Authentic Supplication Number 034.

The Messenger of Allah  said: "When you go to bed make wudhoo' as you do for salat, then lie on your right hand side, and say: 'Allahumma 'aslamtu nafsee 'ilayka, wa wajjahtu wajhee 'ilayka, wa fawwadhtu 'amree 'ilayka, wa 'alja'tu dhahree 'ilayka, raghbatan wa rah-batan 'ilayka, la malja'a wa la manja minka 'illa 'ilayka, amentu bikitabika 'allathee 'anzalta, wa binabiyyika 'allathee 'arsalta (56).

Then if you die that evening you will die on the natural disposition [religion of Islam], and make it the last thing you say."

Footnotes.
(56) O' my 'ilah I have surrendered my self to You, I have directed my face to You, I have entrusted my affairs to You, I have compelled my back to refuge in You, in want and in fright of You, there is no resort nor survival from You except [in turning] to You, I have faith in your book which You have brought down, and in your Prophet which You have sent.

Reporters.
Agreed upon by Bukhari and Muslim, and the presentation of that is that of Al-Bukhari consisting of two narrations. Al-Albani included it in The Authentic of Good Sayings as #34.

Related Hadith(s)