In the C. elegans germline, proliferative cells balance self renewal with entry into meiotic prophase. This decision must normally be coordinated with progression through the mitotic cell cycle in order to prevent a conflict between these two exclusive developmental processes. Currently, it is thought that cells must pass through a specialized meiotic S-phase prior to initiation of meiosis. In order to better understand how cell cycle progression is coordinated with meiotic entry, we analyzed the occurrence of mitotic cell cycle events after inducing meiosis in proliferative cells with the temperature sensitive
glp-1(
bn18) loss-of-function mutant. During this process we observed reproducible kinetics for proliferative cells reaching meiotic prophase that appeared to depend, in part, on mitotic cell cycle position. After initiating mitotic S-phase, proliferative cells appear committed to completing mitosis and loss of
glp-1 did not interfere with completion of mitosis. Our results are consistent with germ cells deciding to enter meiosis during the G1 phase of the cell cycle, allowing cells to proceed through meiotic S-phase prior to meiosis. Initiating meiotic entry at a particular part of the mitotic cell cycle may involve regulation of specific cell cycle factors. To investigate this possibility, we performed an RNAi screen of a panel of cell cycle factors in the
glp-1(
bn18) background at the permissive temperature to identify genes that also regulate the decision to proliferate or enter meiosis. The overall results of this screen indicate that premature meiotic entry is not caused simply by a failure in cell cycle progression since RNAi depletion of the majority of cell cycle regulators and machinery caused cell cycle defects but did not induce premature meiotic entry. In contrast, reduction of
cye-1 or
cdk-2 by RNAi causes germ cells to prematurely enter meiosis in the
glp-1(
bn18) strain. Though
cye-1 is required for mitotic cell cycle progression, lower levels did not appear to interfere with meiotic S-phase. We propose that in the presence of low GLP-1 activity the decision to enter meiotic or mitotic S-phase is regulated by the level of CDK-2/CYE-1 activity with high CDK-2/CYE-1 promoting mitotic S-phase and low CDK-2/CYE-1 activity promoting meiotic S-phase.