Should I tell my boss that I have diabetes?

That really depends... Normally I would say yes, tell them. It will make your life easier. First of all you won't feel that you are hiding something, but more importantly, they can learn how to help you in case you get a hypo or something. But if you know that the business is run on the "survival of the fittest" concept, then I don't know. I think it's something you have to feel in your gut.. 

I think that you should at least let them know that you are diabetic. I have let everyone know that I work with and have shown some how to use the glucagon if it was needed. 

I have always told the people, I have always declared it on an application form, and told my work colleagues what to do, if my mood swings, because of my blood sugar reading.

I work in a large office and have only told those who work close to me, but I never told them straight away....

I would say if you are prone to hypos or get anxious about them and similarly highs then you should tell colleagues because the chances of something happening is high....and they should be prepared....

Yes, but just working in a office,what happens,if you get a phone call that stresses you and,your blood sugar rises, causing your mod to change, the ones who know, will be aware of the cause, but what about all the other members of staff in the office.

I suppose that depends on what actually happens when you are in a bad mood.....

Stress doesn't really put me high or give me mood swings but when it has in the past it's the interaction with others which would bring that bad mood out.....so thats the key.....don't interact until your back in range...or on the way at least...

Also, I'm my office.....which is an office full of male engineers, I wouldn't feel the need to tell them all of my diabetes....even if I was outwardly displaying a mood swing.....

Is that a male thing....who knows..