Q: Is the International Journal of Scientific & Engineering Research indexed in Thomson Reuters?

Although the IJSER website states that it is indexed by Thomson Reuters, we were unable to find it on the Thomson Reuters website under the "engineering and technology journals" category.

This could be because either the journal website or the Thomson Reuters database are not updated. However, we found IJSER listed in the following databases: CrossRef, Google Scholar, CiteFactor, Scribd, and IC Master list (here there are two ISSNs for IJSER, one for a US-based journal and one for an India-based journal. The India-based journal is not indexed). The one you have mentioned is the US based journal. 

Since there are two journals of the same name, (and the Indian one could be a bogus journal) you should make sure are submitting to the right journal. To do this, I’d recommend the following:

• Thomson Reuters also allows users to search by subject/broad area. I suggest that you try the subject-specific search yourself since you’d make the most appropriate choice.
• If you’re still unsure about the journals listing in the Thomson Reuters database, you could query the IJSER journal editor about it, stating that you couldn’t find the journal in the list. Ask the editor if you need to search for the journal under a specific category. This might clear things up. 
• Why don’t you ask your peers/seniors who are from the same field? Is this journal well-known and well-read in your field? 
• If you’re still confused, I’d recommend that you approach your supervisor/department head for help with knowing whether this is a legitimate journal and/or which would be the best journal for you based on your area of research.