I recently lost my adult daughter. she had 5 girls. Her husband's parents are both alive. What is my obligation to say KADDISH is it until the end of shloshim or for the entire year like for a parent?

Shalom, Thank you for your question. Firstly, let me send you condolences at your loss. It sounds like a tragic loss, with five girls and her husband losing their mother and wife – as well as your loss of your daughter. May you be comforted together with the mourners of Zion. As to the halacha. The main custom of saying kaddish is for one's parents. There is no obligation to say kaddish for other close relatives, even though one must mourn for them – such as a spouse, child or sibling. However, some communities have a custom to say kaddish for 30 days for these close relatives who passed away. From your question it seems as though you belong to such a community – as you assume that you must either say kaddish for 30 days or a year. It would though be advisable to check with your local Rabbi as to the local custom. In your case there is an additional question. That is, quite apart from whether a father is obligated to say kaddish over their daughter – who says kaddish over a woman who dies without sons (who would normally be saying the kaddish)? In this case there are differing customs also. From your question it sounds as though there are no grandsons or sons-in-law – but if their were, then according to some opinions they would say kaddish. Being as there are no male offspring, some opinions say the father (ie you) should say the kaddish for the year of mourning (or more exactly, for 11 months, as is the custom). Another custom is that the husband would say the kaddish for this period. At least one of you should take it upon yourselves to say kaddish for the full year. As to the daughters saying Kaddish, the general practice is that women do not say kaddish. However, there are those who follow the halachic ruling that allows women to say kaddish (such as Rav Henkin zt”l, and his grandson Rav Y.H. Henkin shiltah). Those who follow this practice generally only say kaddish from the women's section of the shule together with a man who is also saying kaddish in the men's section. As this is not universally accepted, if the daughters want to say kaddish (additionally to you or their father who will say kaddish for the year), this should be discussed with the Rabbi of the shule to make sure that it is acceptable. Again – may you be comforted for your loss, and merit to see only blessings for you and your whole family.