A new breed of applications and services that combines data and content from diverse sources which we refer to as 'mashups' has grown significantly all across the Internet. One of the most popular mashups comes in the form of web feed mashups relying on syndication technologies such as RSS and Atom. This kind of mashupsaggregates web feeds derived from multiple news websites or blogs and then timely presents them in a single webbased interface. In such systems, it is difficult to know exactly how feed results in data mashups are generated. In particular, it is difficult for users to make determinations about whether information is trusted, considering that source feeds have to pass through several processing operations before the feed results are presented. Therefore, it is crucial that web feed mashupshave to support a mechanism for recording and querying provenance information the information about the process that led to result data. In this paper, we propose aprovenance tracking solution that enables provenance functionality to be facilitated in web feed mashups.We demonstrate how the provenance of feed mashupresults to be determined by means of a provenance query algorithm. Finally, we evaluate our provenance tracking solution in terms of storage consumption for provenance collection, demonstrating predictable storageconsumption and reasonable storage overheads.