This research was conducted with the aims to study causes and effects of the changes in Thai wedding ceremonies, to study concepts and forms of the ceremonies held by individual or group hosts and one-stop wedding planning businesses, and to do comparison studies between the costs charged by those hosts and the wedding planning businesses.This research was limited to study the wedding ceremonies of 10 couples held by individual or group hosts and 10 ceremonies by one-stop wedding planning businesses during the year 2007 in Bangkok area. The subjects of the study were selected from http://www.thaiweddingmall.com and http://www.weddingsquare.com. The researcher was permitted to interview the relevant persons and also to observe the ceremonies on the wedding days.The result can be concluded that1. Concept: At present, most couples held the wedding with the belief to gain luck and prosperity in their family lives. These weddings were simply and economically organized with the shortened process compared to the complicated process in the old tradition. Absolutely, they did not use the wedding planning services as they thought that holding the events by themselves saved the expenses. For the couples using the wedding servicesfrom the businesses besides gaining luck and prosperity, they needed convenience in the wedding preparations and needed to ease their worries about the ceremonial process consisting of many steps. The wedding planning businesses were their options.2. Form: Nowadays, married couples still need Thai traditional wedding ceremonies but they should be in the shortened process skipping some ceremonial steps due to limited time of preparation by themselves. In addition, they are other nations’ wedding ceremonies and other Thai local ceremonies for the couples to choose from and to mix with Thai traditional style. The venues for the wedding are, for example, hotels, associations, and club, as they are easily reachable and convenient for the preparations. The couples using the services from the businesses usually have full process of ceremony as in the old time. In this case, the wedding planning business’s owned venue is popularly used.3. Costs of wedding: There are three kinds of wedding costs: costs for ceremonial rites, costs for reception party, and costs for miscellaneous items. It was found that the reception party costs more than the ceremonial rites.