Madonna has toured a UN project in the African country of Malawi with adopted son David Banda, who was born there.
The pair are also expected to meet with David's natural father, said the BBC's correspondent in the capital Lilongwe.
Madonna, who denies reports that she plans to adopt a second African child, was shown a project where farmers are shown new methods of raising crops.
The US pop star sparked controversy when she adopted David, now 18 months old, from a Malawian orphanage in 2006.
She was accused by adoption groups of using her celebrity status to bypass laws about foreigners adopting from Malawi - allegations she strenuously denied.
Speaking before Madonna set off for Malawi, her spokeswoman Liz Rosenberg said: "She is overseeing the building of a children's healthcare centre. She is absolutely not adopting another baby."
The BBC's Peter Greste in Malawi added that David's father is prepared to meet Madonna, and that the singer is keen to maintain a relationship between her son and Yohane Banda.
David is living with Madonna and her family in London, after the pop star was granted an interim custody order.
Under the court order, David can live with the singer for 18 months, during which time his progress will be reviewed by Malawi officials.
Madonna is trying to avoid the media on her trip with son David
A High Court ruling allows a coalition of human rights groups to monitor the adoption.
Last November, the 48-year-old told the BBC's Newsnight programme she would consider adopting another child from abroad.
"I wouldn't rule it out... but I would like to experience David for a while and see how it works out," she said.
The singer helped set up the Raising Malawi charity, which aims to provide accommodation, food, education and other support to orphans in the country.
Last year, she said she would donate $3m (£1.5m) to the country via the organisation.
On Monday, Madonna toured UN-backed development projects in Mtanga, where farmers are being helped to grow maize and start fish farming.
Her daughter, Lourdes, 10, was with her in Mtanga while David was not.
As well as her adopted son, and Lourdes, she has a six-year-old son, Rocco. The singer is married to British film director Guy Ritchie.