Addressing the public from the balcony of his summer residence, Castel Gandolfo, Benedict said he wanted to continue working for the good of the church even in retirement.
He thanked supporters for their "well-wishes which do me such good", and appealed to fellow Catholics to go forward together.
"Thank you for your friendship and your affection," he said.
"I am simply a pilgrim beginning the last leg of his pilgrimage on this earth, but ... I would still with my heart, with my love, with my prayers, with my reflection, and with all my inner strength, like to work for the common good and the good of the church and of humanity. I feel very supported by your sympathy."
Around 7,000 people gathered to hear from Pope Benedict one last time and there were cheers as he stepped out onto the balcony to address the crowds.
He continued: "Let us go forward with the Lord for the good of the church and the world. Thank you, I now wholeheartedly impart my blessing. Blessed be God Almighty, Father, Son and Holy Spirit. Good night! Thank you all!"
Benedict is to live out his retirement in a secluded monastery within the walls of the Vatican. He has spoken of his intention to spend his time in prayer and reflection.
Following his resignation at 8pm today, his official title will be Pope Emeritus.
In a farewell gathering with over a hundred cardinals at the Vatican this morning, he pledged his obedience to his successor.
"I will be close to you in prayer, especially in the next few days, so that you are fully accepting of the action of the Holy Spirit in the election of the new pope," he said.
"May the Lord show you what he wants. Among you there is the future pope, to whom I today declare my unconditional reverence and obedience."