This manga is extremely beautiful and deserves #1 on this list. Though #2 is a close second. It is really a sad story. The characters are super deep. The very beginning I hated the main character girl. However, she grows so much that I ended up loving her by the end. The guy had some sad circumstances and because of that he never really had a chance in hell. The last couple chapters are so sad I was crying like a fool. Honestly if you don't cry in the end... I don't know if you have feelings. 

This manga is really good. It's also one I have a hard time reading over. I love a good tragedy but I don't want to wallow in it. This should be read at least once by anyone. It's about a guy who falls for a girl. Both are dying though they both try to keep it from eachother. The guy was a playboy and the girl had strict morals so she forced him to appologize to every woman before she would be with him for real. The ending of  this one... if you don't cry at how sad and sweet it is your not human.

This is a beautiful manga. It's extremely sad at the end but also extremely heartwarming. It's only one volume long. Some sites don't carry all 4 chapters so make sure you got the whole thing before you start reading. Unless you want to switch sites later. I cried while reading this one.

Another extremely heartwarming yet sad manga. That is well worth the read. It's been a long time since I read it. I'm going to read it today and write more about it after.

This manga is really great. It doesn't have a lot of romance but it's more like friendship at the end of lives. It's got really sweet and really funny parts but it's also incredibly sad.

This manga is pretty tragic but it manages a happy ending. Plus it's based in real life issues and give true facts about HIV.

This is a compilation of stories. The first is my favorite. It's sad at points but has a happy ending. What made this on this list though is for the story after the first one. Both characters are dying. The arts not to great in any of these stories but all of them are really deep.

This is one most people have read. However, if you're a shoujo romance buff who likes tragedy. If you have not read this you should. It's about a girl who a demon takes in... but humans grow faster than demons.... and die quicker too.