3 Days 

Mount Meru is the fifth highest mountain on the African continent and the second highest in Tanzania and dominates the Arusha National Park .It reaches 4,566 metres (14,980 feet) in height but has lost much of its bulk due to an eastward volcanic blast about 8,000 years ago.
Mount Meru most recently had a minor eruption about a century ago. The several small cones and craters seen in the vicinity reflect numerous episodes of volcanic activity 

Itinerary

Day 1: Moshi -to momela Gate,trekking to Meriakamba Hut
We drive from Moshi to Momela Gate. After a short registration at the Gate our walk will begin with full armed ranger escorting us, simply we can see along the way the wild animals including elephants, zebras, and giraffe , monkeys, antelope, and often elephants along the route. Dinner and overnight night at Miriakamba Hut.

Day 2: Meriakamba Hut - Saddle Hut .
The walk from Miriakamba Hut to the saddle below Little Meru is a short day but a steep climb. The walk will take us slowly along the ridge for a spectacular view of the Meru Crater and the impressive Ash Cone. After hot lunch at Saddle Hut we can make a short climb to the summit of Little Meru (3,820m) for superb views just before sunset.

Day 3: Saddle Hut to summit (4566m)– Back to momela Gate to Moshi
We start early at around 1:30 a.m. to climb steeply to Rhino Point (3,800 m.) and on to Cobra Point (4350m). We reach the summit (4,566 m) on time for sunrise there is a possibility to see Kilimanjaro Peak above the clouds. The final part of the climb is along a spectacular narrow ridge line between the sheer inner cliffs and the sloping outer wall of the crater. We take a short rest and brunch at Saddle Hut before continuing the descent to the Momella gate. The returning transfer will be waiting at Momella Gate to pick you to Moshi at your hotel.