Why doesn't icloud sync my Imac (ICAL) calendar with my Iphone calendar?

Are you syncing your iMac with your iCloud account with Calendar syncing set to ON? If so, what happens when you try to sync? Do calendar events sync either direction?

You have to be running OS X 10.7.4 or later and have iCloud syncing configured in System Preferences>iCloud with "Calendars & Reminders" checked, as described here: http://www.apple.com/icloud/setup/mac.html. Also go to iCal>Preferences>Accounts and confirm that iCloud is listed as an Account and is enabled in Account Information (I'm doing this part from memory as I am running Mountain Lion now and can't check on my Mac).

If all that looks correct, then check to be sure that you are entering your calendar events in the iCloud section of iCal (as described here: http://support.apple.com/kb/HT4968). If you are, then check to be sure that these events appear in your calendar on icloud.com.

Also be sure that you are entering events on your iPhone on your iCloud calendar and not some other calendar such as On My iPhone. If you are, see if these events appear in your calendar on icloud.com.

Many are having the same problem syncing with Yosemite and IOS 8 between macs and iphones, etc.

Same here. No ical or or notes sync. haven't even explored contacts syncs.

with my recent upgrade to iphone6, and yosemite, i had to wipe both devices, taking A LOT of time!

For all the money i give to Apple, I find this unacceptable!

How many billions$? is Apple sitting on, and they can't get this right?

I've tried many of the suggestions posted and these expensive devices still don't sync properly.

itunes does synch over wifi with new music content, I'll give them that. But that's only one aspect.