Uhuru Kenyatta attended a special Igad summit in Mogadishu on Tuesday, on the first visit to Somalia by a Kenyan president in three decades.
The President was received by his counterpart Hassan Mohamoud at Aden Adde International Airport.
Uhuru and Mohamoud held brief bilateral talks at a hotel near the airport before the summit.
The summit discussed progress Somalia has made on security and stability, its upcoming vote for a new parliament and president, and the situation in South Sudan.
The meeting was the first of its kind in Mogadishu since Somalia plunged into conflict in 1991.
"It symbolises the reconstruction of Somalia and Somalia coming back to the (family of) nations," Foreign Minister Abdusalam Omer told Reuters as heads of state flew in.
"It signifies that we are defeating international terrorism."
Somalia has hosted visits of individual heads of state. But Omer said this was the first summit gathering for about four decades, since the rule of President Siad Barre, whose toppling in 1991 was followed by two decades of conflict.
Many senior visitors to Mogadishu stay in the airport area, a compound surrounded by high blast walls with barbed wire and patrolled by Amisom. The summit was held just outside the perimeter at a nearby hotel.
"The presence of the heads of state in Somalia is a clear dividend of returning stability in the country," the peacekeeping force said in a statement.
Streets were shut down to traffic in the capital, for the day-long summit that Ethiopia (Prime Minister Hailemariam Desalegn), Uganda (President Yoweri Museveni), Djibouti and Sudan also attended.
Kenya, Uganda and Ethiopia are among the countries with troops in Somalia.
Ordinary Somalis were forced to walk around the capital as traffic was blocked from many streets. Al Shabaab has often used vehicles packed with explosives to launch attacks on sites in Mogadishu, blowing up security posts so fighters can storm in.
Mogadishu still bears the scars of war, with many buildings little more than bombed out shells. But there has been a construction boom in recent years, that has seen new buildings erected, often financed by Somalis returning from abroad.
Al Shabaab, which once ruled most of Somalia, has been waging an insurgency to topple the Western-backed government of Mohamud, who seeks re-election later this year.
Security concerns mean only a fraction of Somalia's 11 million people will vote in the election, with 14,000 people gathered from the federal states choosing the 275 members of parliament, before the lawmakers then pick the president.
But that is still an improvement on the 135 elders who chose parliament in 2012, and which in turn picked Mohamud.