Nigeria's ambassador in Kampala has accused a Ugandan minister of having "learning problems" after he made comments criticising Nigeria.
President Museveni has been asked to investigate
Uganda's Environment Minister Kahinda Otafiire said the opposition was unfit to govern, "like Nigerians who don't know how to count themselves".
Nigeria has struggled to conduct a reliable census for more than half a century and it is a sensitive issue.
Envoy CD Orike said the minister should educate himself on Nigerian successes.
"In every field of human endeavour Nigerians have excelled in Africa."
He then proceeded to list a number of famous Nigerians including sports stars and musicians.
"That Mr Otafiire did not know all these facts about Nigeria is clear evidence that he must have some learning problems," he said.
"Otafiire may do well to take useful lessons about Nigeria from some of his professional colleagues in the Ugandan military who were trained in Nigeria."
Mr Orike called on Uganda's President Yoweri Museveni to caution the minister.
In Nigeria, political parties have been quarrelling about what questions should be asked in the next planned population census.