The fighters, riding in five pickup trucks, opened fire on the policemen as many of them were eating lunch at the post in Shoravak, a district in southern Kandahar province near the Pakistan border, said Chief District Administrator Haji Abdul Majeed.
The ensuing hour-long battle left five other policemen wounded, Majeed said.
He said five of the attackers' bodies were left behind before they retreated toward the Pakistan border.
The injured policemen have been moved to a hospital in Kandahar, the province's capital, Majeed said.
"The bodies of the Taliban are with us and we have seized their five AK-47 rifles, a few grenades and two rockets," he said from Shoravak.
Slideshow: Escape from Bagram
None of the slain suspected Taliban was reported to be a senior figure in the militia, which a US military campaign ousted from power in late 2001 for harboring al-Qaeda.
The latest fighting comes amid a continuing spate of bloodshed that has left more than 700 people dead in three months and threatened to unhinge three years of progress toward peace in Afghanistan.
US and Afghan officials have warned that the violence is likely to worsen ahead of the country's parliamentary elections slated for September.
On Thursday, two policemen were injured in a bomb explosion at a voter registration office in the capital of southeastern Khost province, said Khost Police Chief Mohammed Ayub.
Ayub blamed the attack on "enemies of the election" an indirect reference to the Taliban.
"The entire country of Afghanistan knows who these enemies are," he said. "They are trying to sabotage security before the elections."
Authorities have expressed concern over a steady stream of Taliban attacks against the government, saying they could threaten the vote, seen as a key step toward stability.
Suspected Taliban insurgents have been particularly active in areas in Afghanistan near the Pakistan border in recent months.
The explosion in Khost came on the same day that an Afghan National Army soldier was killed and another injured when suspected Taliban fighters fired rockets at their base in Paktia province, near Pakistan.
Maj. Gen. Rehmatullah Raufi, the top army commander in Paktia, said the base was attacked.
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