What kind of uke is it? Depending on the quality, it could detune faster.
What kind of strings do you have?
Is your uke new? If your uke is new, it will take a week or so for the strings to settle.
Did you just restring it? Same as above, it just restringed, they need to settle.
Yup, very common problem. It's something we just learn to live with when playing new strings... tune-strum-tune-strum-tune-strum-tune etc etc etc. It's a real chore, but they settle eventually.
The more you play those strings the quicker they'll stretch out and stabilise.
Well, if it was a cheaper uke it might have come with less-than-optimal strings, so a change to a known quality brand (like Aquila or Worth) might help. Of course, then you have to start the settling in process all over again.
Looked up the model # and the pic on the Sam Ash site shows geared tuners.
keep in mind when you re-string it, it will go out of tune almost as soon as you tune it back up. This is because the new strings need to stretch. If you place your thumb on top of the string, and your first 2 fingers under and do kind of a bottle opener motion, you can help the stretching process. here is a good vid NukeDOC did on youtube if your more a visual person.
If you have geared tuners, do NOT tighten the cog screw too much. Friction tuners need to be fairly tight to stop slippage, but even those should not be tightened to extremes. The geared kind only need to be tightened enough to stop the screw working loose. Over tightening causes premature wear to the cog, the worm gear and the tuner buttons.