Abstract This paper is an attempt to highlight the problems faced by industrial rheologists. The problems are far more complex than subjects of usual academic pursuit. Because of the lack of scientific methods in both theory and instruments, the industrial rheologist often resort to empirical approach such as a use of the processing machines for processability evaluation. More fundamental approach is desirable. The examples are taken from high density polyethylenes and the period was 1960-1970. Although industry found solutions to the problems, the fundamental understandings have not been developed sufficiently.