There is never a wrong time to invest in mutual funds for retirement. So, if you're still looking for the best mutual funds, the Zacks Mutual Fund Rank can be a great guide.

The easiest, most reliable way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. The Zacks Mutual Fund Rank, which covers over 19,000 mutual funds, has helped us identify three outstanding options that are perfect for any long-term investors' portfolios that is retirement-focused.

Let's break down some of the mutual funds with the top Zacks Mutual Fund Rank and the lowest fees.

AB Large Cap Growth R (ABPRX Quick QuoteABPRX - Free Report) : 1.09% expense ratio and 0.48% management fee. ABPRX is a Large Cap Growth option; these mutual funds purchase stakes in numerous large U.S. companies that are expected to develop and grow at a faster rate than other large-cap stocks. With annual returns of 12.37% over the last five years, this fund is a winner.

JPMorgan Disciplined Equity I (JDESX Quick QuoteJDESX - Free Report) . Expense ratio: 0.35%. Management fee: 0.25%. JDESX is part of the Large Cap Blend section, and these mutual funds most often invest in firms with a market capitalization of $10 billion or more. By investing in bigger companies, these funds offer more stability, and are often well-suited for investors with a "buy and hold" mindset. This fund has managed to produce a robust 11.88% over the last five years.

T. Rowe Price Science & Technology Fund (PRSCX Quick QuotePRSCX - Free Report) . Expense ratio: 0.84%. Management fee: 0.63%. Five year annual return: 10.21%. PRSCX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach.

These examples highlight the fact that there are some astonishingly good mutual funds out there. If your advisor has you in the good ones, bravo! If not, you may need to have a talk.