If they fired you because you were diabetic--and not for some other reason; that is, the fact that you are diabetic does not mean that you cannot be fired for other causes--AND it is the case that you could safely and properly do the job, then you may have a claim for illegal discrimination. The law does not allow employers to fire people because of a disability, and disabetes may count as a disability for this purpose. The key issue is whether you could do the job--an employer does not have to employ someone who cannot do the job they were hired for.So, for example--and I am not very knowledable about diabetes, so if this example is factually wrong, I apologize--say that being diabetic means that you run the risk of passing out if you cannot eat the right foods at the proper times to maintain the proper blood sugar levels. If the job involves operating heavy equipment or driving long distances, where it is possible you could be unable to eat when you need to, and therefore possibly pass out while operating machinery or a vehicle, the employer may be justified in terminating you. The employer is not required to accept that risk.If you feel that you could do the job, then it would be worthwhile for you to consult with an employment law attorney to discuss the situation and your rights in greater detail.