Two rangers were hurt during the battle in West Pokot county, said officials from Kenya's Wildlife Service (KWS).
They said 50kg (110lb) of elephant tusks and AK-47 rifles were recovered.
Kenya has recently taken a more aggressive stance against poaching as it combats a surge in demand for ivory from Asia, despite a long-standing ban on the international trade.
KWS spokesman Paul Udoto said on Saturday that rangers were determined to make poaching "a high-cost, low-benefit activity".
The KWS says about 100 elephants are killed each year in Kenya by poachers.
Ivory from elephants is often smuggled to Asia for use in ornaments, while rhino horns are used in traditional medicine.
Wildlife rangers have shot dead five suspected ivory poachers during a gun battle in western Kenya.